Remove RaftReplicator and move hearbeat logic to the leader

This makes more sense. The RaftReplicator does not seem to add any value.

Change-Id: Id3cf8ecbd2493b35c1a32382d65876795a78fa30
Signed-off-by: Moiz Raja <moraja@cisco.com>
Merge "Remove RaftReplicator and move hearbeat logic to the leader"