Save and load database history in Redis

As a user I would like to be able to store database history events in Redis.
I propose to add an implementation of AbstractDatabaseHistory that will store and retrieve the database history in Redis.
As with the RedisOffsetStore, this can be placed in the sink for now, and moved over later, unless you feel it should be placed elsewhere?
Happy to issue a PR for this. Let me know if there are any specific implementation guidelines.