Changed key actors to use bounded mailbox

1. Changed key actors in clustering components to use
bounded mailbox.

2. Implementation of Bounded mailbox queue changed to
 use deque as its required by Shard Actors.

3. Cleanup of hard coded values.

Change-Id: I9fb87e1857f2aa9fee0819c4dff63ca3c967ec60
Signed-off-by: Abhishek Kumar <abhishk2@cisco.com>