NormalizedNode serialization using protocol buffer

Utilization of CreateTransactionReply protocol buffer
message in Distributed Datastore

Subsequent commits will utilize other portocol buffer
messages in Distributed Datastore

Change-Id: I64c08d1998bab29a92351fc1fd5897d0faaf4081
Signed-off-by: Basheeruddin Ahmed <syedbahm@cisco.com>
Signed-off-by: Moiz Raja <moraja@cisco.com>