Split starting and stopping master IP and daemons

lib/backend.py
* split StartMaster() in ActivateMasterIp() and StartMasterDaemons()
* split StopMaster() in DeactivateMasterIp() and StopMasterDaemons()

lib/server/noded.py, lib/rpc.py
* adapt the call chains to the new functions, define new RPCs

lib/bootstrap.py, lib/cmdlib.py, lib/server/masterd.py
* use the new RPCs

Signed-off-by: Andrea Spadaccini <spadaccio@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>