Upgrade RpcControllerFactory and HBaseRpcController from Private to LimitedPrivate(COPROC,PHOENIX)

Phoenix has had an unrecognized dependency on RpcControllerFactory and HBaseRpcController for about four years. These interfaces are used to override setPriority for appropriate dispatch of requests for Phoenix system or index tables to separate pools. This is a reasonable use of these interfaces but the audience annotations were never updated to reflect this usage. Also seems reasonable to do so as there has been no issue here for four years. (Phoenix commit was made in 2017.) Make it official.