Restoration of redis servers from backup

[YannikBramkamp]

Add ability to restore a redis server from an rdb dump.

The basic workflow for this operation is the following:

1. Turn off appendonly on the server using redis-cli
2. Shutdown the server using redis-cli
3. Stop the redis service
4. Rename or remove old .aof and .rdb files for safety
5. Copy desired .rdb
6. Start the redis service

The primary issue is accomplishing 3 and 6, considering that these steps would require os-specific interactions