when in libmpv mode there is no need to for logging and reading options.
this also prevents possible race conditions with the usage and deinit of
the mpv_handler.
since cocoa is initialising mpv and does several things before the mpv
core does anything and the mpv_handle was passed to the App, this can be
used to log such things before the mpv logging is available. helpful for
debugging especially bundle related things.
the logger mapping looks a bit unintuitive but error is basically yellow
what our warning is and fatal is red what our error is.
add new app_bridge objc file for bridging between mpv core and app
functionality. replace old EventsResponder singleton with AppHub.
another step to clean up all App functionality and have one central
place for it.