NIFI-4061 Initial version of RedisStateProvider
- Adding PropertyContext and updating existing contexts to extend it
- Added embedded Redis for unit testing
- Added wrapped StateProvider with NAR ClassLoader in StandardStateManagerProvider
- Updating state-management.xml with config for RedisStateProvider
- Renaming tests that use RedisServer to be IT tests so they don't run all the time
This closes#1918.
Peter Turcsanyi
Joe Witt
Denes Arvay
Bryan Bende