Move more things out of FrigateApp (#13897)

* Moved FrigateApp.init_config() into FrigateConfig.load()

* Move frigate config loading into main

* Store PlusApi in FrigateConfig

* Register SIGTERM handler in main

* Ensure logging is setup during config parsing

* Removed pointless try

* Moved config initialization out of FrigateApp

* Made FrigateApp.shm_frame_count into a function

* Removed log calls from signal handlers

python's logging calls are not re-entrant, which caused at least one of
these to deadlock randomly.

* Reopen stdout/err on process fork

This helps avoid deadlocks (https://github.com/python/cpython/issues/91776).

* Make mypy happy

* Whoops. I might have forgotten to save.

Truly an amateur mistake.

* Always call FrigateApp.stop()

frigate/events/audio.py

@@ -76,16 +76,8 @@ def listen_to_audio(
     stop_event = mp.Event()
     audio_threads: list[threading.Thread] = []
 
-    def exit_process() -> None:
-        for thread in audio_threads:
-            thread.join()
-
-        logger.info("Exiting audio detector...")
-
     def receiveSignal(signalNumber: int, frame: Optional[FrameType]) -> None:
-        logger.debug(f"Audio process received signal {signalNumber}")
         stop_event.set()
-        exit_process()
 
     signal.signal(signal.SIGTERM, receiveSignal)
     signal.signal(signal.SIGINT, receiveSignal)
@@ -104,6 +96,11 @@ def listen_to_audio(
             audio_threads.append(audio)
             audio.start()
 
+    for thread in audio_threads:
+        thread.join()
+
+    logger.info("Exiting audio detector...")
+
 
 class AudioTfl:
     def __init__(self, stop_event: mp.Event, num_threads=2):