[FAB-5533] Add private data into state payload

Gossip state tranfer response include payload field to replicate ledger
block, to support transfer of private data while responding on state
transfer request. This commit add new field into state transfer response
message payload.

Change-Id: I840bf5a7a7fac85b65049e5ce91b44f1cb9277ef
Signed-off-by: Artem Barger <bartem@il.ibm.com>

Author: C0rWin