1. Shard manager creates Shard and mark them un-initialized.
Shard completes recovery and onRecoveryComplete, sends a
message to Shard manager to mark it initialized.
If a request for Shard comes to Shard manager and the
shard is not initialized, it sends ActorNotInitialized
message.
2. Normalizes and refactors ActorContext.
3. Adds AbstractUntypedPersistentActorWithMetering to meter
ShardManager.
Change-Id: Ibf15a2ef56422bda53067039d2271a719b6b2ce3
Signed-off-by: Abhishek Kumar <abhishk2@cisco.com>