[Distributed]Add authentication in MetaSnapshot

Although AuthorPlans are supported, authentication information like users, roles, privileges are not concluded in the MetaSnapshot, so when meta logs are removed, the stale nodes will not be able to catch up with the leader.

Authentication information can be directly added into current MetaSnapshot so that the receiver can recover from it without further transmission or as a descriptor in the MetaSnapshot through which the receiver can know where to pull the information.