* config options
* metrics
* stop and restart ffmpeg processes
* dispatcher
* frontend websocket
* buttons for testing
* don't recreate log pipe
* add/remove cam from birdseye when enabling/disabling
* end all objects and send empty camera activity
* enable/disable switch in ui
* disable buttons when camera is disabled
* use enabled_in_config for some frontend checks
* tweaks
* handle settings pane with disabled cameras
* frontend tweaks
* change to debug log
* mqtt docs
* tweak
* ensure all ffmpeg processes are initially started
* clean up
* use zmq
* remove camera metrics
* remove camera metrics
* tweaks
* frontend tweaks
* Subclass Process for audio_process
* Introduce custom mp.Process subclass
In preparation to switch the multiprocessing startup method away from
"fork", we cannot rely on os.fork cloning the log state at fork time.
Instead, we have to set up logging before we run the business logic of
each process.
* Make camera_metrics into a class
* Make ptz_metrics into a class
* Fixed PtzMotionEstimator.ptz_metrics type annotation
* Removed pointless variables
* Do not start audio processor when no audio cameras are configured
