auth/AuthServiceHandler: keep track of global_id and whether it is new

auth/AuthServiceHandler: keep track of global_id and whether it is new

AuthServiceHandler already has global_id field, but it is unused.
Revive it and let the handler know whether global_id is newly assigned
by the monitor or provided by the client.

Lift the setting of entity_name into AuthServiceHandler.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
(cherry picked from commit b50b6abd60e730176a7ef602bdd25d789a3c467d)

Conflicts:
	src/auth/cephx/CephxServiceHandler.cc [ bufferlist vs
	  ceph::buffer::list ]
	src/auth/cephx/CephxServiceHandler.h [ ditto ]
	src/auth/none/AuthNoneServiceHandler.h [ ditto ]