Initial implementation of ListenerRegistration actor and all related messages

Change-Id: I4f63532983a2e272b610a61f093242e34867ed70
Signed-off-by: Moiz Raja <moraja@cisco.com>
Introduce ShardStrategy and related code

Change-Id: I0df1f18f7b3488acae440e3375e155ae7ee06abf
Signed-off-by: Moiz Raja <moraja@cisco.com>
Merge changes I0df1f18f,I4f635329

* changes:
  Introduce ShardStrategy and related code
  Initial implementation of ListenerRegistration actor and all related messages