Shutdown hang (#11793)

* intentionally handle queues during shutdown and carefully manage shutdown order

* more carefully manage shutdown to avoid threadlocks

* use debug for signal logging

* ensure disabled cameras dont break shutdown

* typo

frigate/output/output.py

@@ -38,6 +38,7 @@ def output_frames(
     stop_event = mp.Event()
 
     def receiveSignal(signalNumber, frame):
+        logger.debug(f"Output frames process received signal {signalNumber}")
         stop_event.set()
 
     signal.signal(signal.SIGTERM, receiveSignal)