Map and possibly remove Deprecated code

This is follow-up of CASSANDRA-18912. We should scan the project and document what was deprecated and when (based on "since" added to Deprecated annotation).

Once this is done, we need to identify what should be removed and what should stay.

It is questionable if this ticket will result in some actual code change. I think we should firstly just map what was deprecated to have a bigger picture where we are. Then we can discuss what to actually remove.