[ZEPPELIN-4541]. Add api to checkpoint paragraph output between interpreter and zeppelin-server

### What is this PR for?
In ZEPPELIN-4525 we add support of Shiny app in R interpreter, because when we refresh the note page, the iframe is not displayed, the root cause is that we only save note when paragraph is finished, while we launch shiny app in zeppelin, the paragraph is in RUNNING state. In this PR, we add api to checkpoint paragraph output so that user can see the output even after refresh note.

### What type of PR is it?
[ Improvement ]

### Todos
* [ ] - Task

### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-4541

### How should this be tested?
* CI pass

### Screenshots (if appropriate)
![shiny_app](https://user-images.githubusercontent.com/164491/71878752-6428a800-3167-11ea-92b5-f388650d19f5.gif)

### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No

Author: Jeff Zhang <[email protected]>

Closes #3589 from zjffdu/ZEPPELIN-4541 and squashes the following commits:

38f8ba8 [Jeff Zhang] [ZEPPELIN-4541]. Add api to checkpoint paragraph output between interpreter and zeppelin-server

Author: zjffdu

rlang/src/test/java/org/apache/zeppelin/r/ShinyInterpreterTest.java

@@ -28,6 +28,7 @@
 import org.apache.zeppelin.interpreter.InterpreterResult;
 import org.apache.zeppelin.interpreter.InterpreterResultMessage;
 import org.apache.zeppelin.interpreter.LazyOpenInterpreter;
+import org.apache.zeppelin.interpreter.remote.RemoteInterpreterEventClient;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -42,6 +43,7 @@
 import static junit.framework.TestCase.assertEquals;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+import static org.mockito.Mockito.mock;
 
 public class ShinyInterpreterTest {
 
@@ -240,6 +242,7 @@ protected InterpreterContext getInterpreterContext() {
             .setInterpreterOut(new InterpreterOutput(null))
             .setLocalProperties(new HashMap<>())
             .setInterpreterClassName(ShinyInterpreter.class.getName())
+            .setIntpEventClient(mock(RemoteInterpreterEventClient.class))
             .build();
     return context;
   }

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/remote/RemoteInterpreterEventClient.java

@@ -235,6 +235,15 @@ public synchronized void runParagraphs(String noteId,
     }
   }
 
+  public synchronized void checkpointOutput(String noteId, String paragraphId) {
+    try {
+      intpEventServiceClient.checkpointOutput(noteId, paragraphId);
+    } catch (TException e) {
+      LOGGER.warn("Fail to checkpointOutput of paragraph: " +
+              paragraphId + " of note: " + noteId, e);
+    }
+  }
+
   public synchronized void onAppOutputAppend(
       String noteId, String paragraphId, int index, String appId, String output) {
     AppOutputAppendEvent event =

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/AngularObjectId.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class AngularObjectId implements org.apache.thrift.TBase<AngularObjectId, AngularObjectId._Fields>, java.io.Serializable, Cloneable, Comparable<AngularObjectId> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("AngularObjectId");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/AppOutputAppendEvent.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class AppOutputAppendEvent implements org.apache.thrift.TBase<AppOutputAppendEvent, AppOutputAppendEvent._Fields>, java.io.Serializable, Cloneable, Comparable<AppOutputAppendEvent> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("AppOutputAppendEvent");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/AppOutputUpdateEvent.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class AppOutputUpdateEvent implements org.apache.thrift.TBase<AppOutputUpdateEvent, AppOutputUpdateEvent._Fields>, java.io.Serializable, Cloneable, Comparable<AppOutputUpdateEvent> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("AppOutputUpdateEvent");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/AppStatusUpdateEvent.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class AppStatusUpdateEvent implements org.apache.thrift.TBase<AppStatusUpdateEvent, AppStatusUpdateEvent._Fields>, java.io.Serializable, Cloneable, Comparable<AppStatusUpdateEvent> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("AppStatusUpdateEvent");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/InterpreterCompletion.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class InterpreterCompletion implements org.apache.thrift.TBase<InterpreterCompletion, InterpreterCompletion._Fields>, java.io.Serializable, Cloneable, Comparable<InterpreterCompletion> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("InterpreterCompletion");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/OutputAppendEvent.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class OutputAppendEvent implements org.apache.thrift.TBase<OutputAppendEvent, OutputAppendEvent._Fields>, java.io.Serializable, Cloneable, Comparable<OutputAppendEvent> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("OutputAppendEvent");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/OutputUpdateAllEvent.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class OutputUpdateAllEvent implements org.apache.thrift.TBase<OutputUpdateAllEvent, OutputUpdateAllEvent._Fields>, java.io.Serializable, Cloneable, Comparable<OutputUpdateAllEvent> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("OutputUpdateAllEvent");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/OutputUpdateEvent.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class OutputUpdateEvent implements org.apache.thrift.TBase<OutputUpdateEvent, OutputUpdateEvent._Fields>, java.io.Serializable, Cloneable, Comparable<OutputUpdateEvent> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("OutputUpdateEvent");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/ParagraphInfo.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class ParagraphInfo implements org.apache.thrift.TBase<ParagraphInfo, ParagraphInfo._Fields>, java.io.Serializable, Cloneable, Comparable<ParagraphInfo> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("ParagraphInfo");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/RegisterInfo.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class RegisterInfo implements org.apache.thrift.TBase<RegisterInfo, RegisterInfo._Fields>, java.io.Serializable, Cloneable, Comparable<RegisterInfo> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("RegisterInfo");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/RemoteApplicationResult.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class RemoteApplicationResult implements org.apache.thrift.TBase<RemoteApplicationResult, RemoteApplicationResult._Fields>, java.io.Serializable, Cloneable, Comparable<RemoteApplicationResult> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("RemoteApplicationResult");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/RemoteInterpreterContext.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class RemoteInterpreterContext implements org.apache.thrift.TBase<RemoteInterpreterContext, RemoteInterpreterContext._Fields>, java.io.Serializable, Cloneable, Comparable<RemoteInterpreterContext> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("RemoteInterpreterContext");
 

zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift/RemoteInterpreterEvent.java

@@ -24,7 +24,7 @@
 package org.apache.zeppelin.interpreter.thrift;
 
 @SuppressWarnings({"cast", "rawtypes", "serial", "unchecked", "unused"})
-@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-06")
+@javax.annotation.Generated(value = "Autogenerated by Thrift Compiler (0.13.0)", date = "2020-01-07")
 public class RemoteInterpreterEvent implements org.apache.thrift.TBase<RemoteInterpreterEvent, RemoteInterpreterEvent._Fields>, java.io.Serializable, Cloneable, Comparable<RemoteInterpreterEvent> {
   private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("RemoteInterpreterEvent");