Cleanup the hyperlight-host public API

[jprendes]

Currently the following items are publicly exported from hyperlight-host, and I believe many of them were never intended to be public, we should fix that.
For items that are not intended to be public, but are needed by macros, we should mark them as #[doc(hidden)], and ideally be moved to a properly named module, something like _private

Crossed out are the items I believe don't need to be public.

List of all items

Structs

• func::HostFunction
• hypervisor::VirtualCPU
• mem::memory_region::MemoryRegion
• mem::memory_region::MemoryRegionFlags
• mem::ptr::RawPtr
• mem::shared_mem::ExclusiveSharedMemory
• mem::shared_mem::GuestSharedMemory
• mem::shared_mem::HostMapping
• mem::shared_mem::HostSharedMemory
• sandbox::config::SandboxConfiguration
• sandbox::initialized_multi_use::MultiUseSandbox
• sandbox::snapshot::Snapshot
• sandbox::uninitialized::GuestBlob
• sandbox::uninitialized::GuestEnvironment
• sandbox::uninitialized::UninitializedSandbox

Enums

• error::HyperlightError
• func::ParameterValue
• func::ReturnType
• func::ReturnValue
• hypervisor::HyperlightExit
• mem::memory_region::MemoryRegionType
• sandbox::uninitialized::GuestBinary

Traits

• func::ParameterTuple
• func::Registerable
• func::ResultType
• func::SupportedParameterType
• func::SupportedReturnType
• hypervisor::InterruptHandle
• mem::shared_mem::AllValid
• mem::shared_mem::SharedMemory
• sandbox::Callable

Macros

• and
• debug
• log_then_return
• new_error
• or

Functions

• sandbox::is_hypervisor_present
• sandbox::is_supported_platform

Type Aliases

• Result
• sandbox::ExtraAllowedSyscall

[jprendes]

From the things I believe should be public, they live in the following modules:

• func: 9 items, most supporting the HostFunction trait, the only other item is the Registerable trait.
  {HostFunction, ParameterValue, ReturnType, ReturnValue, ParameterTuple, Registerable, ResultType, SupportedParameterType, SupportedReturnType}
• sandbox: 9 items, this is the most varied module.
  {config::SandboxConfiguration, initialized_multi_use::MultiUseSandbox, snapshot::Snapshot, uninitialized::GuestBlob, uninitialized::GuestEnvironment, uninitialized::UninitializedSandbox, uninitialized::GuestBinary, Callable, ExtraAllowedSyscall}
• error: 1 item
  {HyperlightError}
• :: (crate's root): 3 items, macros and Result
{log_then_return, new_error, Result}

and one outlier, hypervisor::InterruptHandle, which arguably should belong to a different module, probably sandbox.