This adds functions to the frontend api to start/stop the virtual
camera, to check if it is active and adds function to get the output
reference. It also adds api events for when the virtual camera is
started or stopped.

Custom streaming service URLs beginning with `ftl` are handled by the
`ftl_output` plugin.

Fixes #4031

It seems Qt on various flavours of Linux behaves erratically when scaled,
and for the moment macOS doesn't require fractional scaling support.

This commit can be reverted when Qt fixes issues on their side.

When a media source is set to use a URL, always fully shut down the
media when stopped. This ensures that the media will do a full
reconnect after having been stopped.

When connection to FTL ingest is lost, ftl_event() calls
obs_output_signal_stop() to trigger a reconnect. However, during the
reconnect delay, send_thread is still waiting on send_sem semaphore.
After the delay, ftl_stream_start() is called, which in turn resets
the semaphore and creates a new send_thread. Old send_thread now exits
the loop and triggers another reconnect and the whole process repeats
again. The fix resets the semaphore in ftl_event() so the old
send_thread exits immediately.

Also remove use of deprecated [NSProcessInfo operatingSystem]. It always
returns the NSMACHOperatingSystem.

Also stop parsing [NSProcessInfo operatingSystemVersionString]. The
documentation explicitly says "not for parsing".

This commit prevents a crash in, for example, Linux configurations
where PulseAudio is disabled, which leads into 'mod' being 'null',
which in turn leads into a segmentation fault when an ALSA source
is selected.

Closes https://github.com/obsproject/obs-studio/issues/3485

The capture loop errors are now logged as such.
Increased the amount of information logged in debug mode, including
state of all buffers on timeout.
Add device name to all capture loop debug output, especially useful when
debugging issues with multiple v4l2 video streams.

Updates the AUTHORS list to the state of b5348be70

Adds all authors that are in the git shortlog multiple times, as in with multiple names and / or emails, as well as those that were authors list

Modify game capture shared textures to be typeless if they could
potentially need SRGB and non-SRGB views in the future.

These capture APIs have been updated: D3D 10/11/12, Vulkan.

D3D8 capture does not use shared textures.

D3D9 and GL interop do not support typeless textures.

The new game capture DLL should be compatible with old versions of OBS.

Also removed a lot of dead code around pointless SRV/RTV support.

In the future, we may share or wrap typeless textures to support SRGB
and non-SRGB views.

Make sure libobs links all libraries needed to satisfy symbols in the
library.

Fixes obsproject/obs-studio#3924

Use color picker with alpha to restore color overlay functionality.

Fixes obsproject/obs-studio#3979.

CI: Update Qt and Deps on Windows

UI: Enable HW acceleration switch for browser sources on Mac

libobs: Add texture sharing support for macOS/OpenGL

macOS hardware acceleration
multiprocess on macOS

This lock causes a deadlock when freeing the JACK client while a
process callback is pending:

deactivate_jack -> locks mutex
   JACK thread -> calls jack_process_callback
   jack_process_callback -> blocks on mutex
jack_client_close -> joins JACK thread
(deadlock as the process callback never returns)

Instead, just don't lock the mutex. This is only mutexing on
creation/destruction of the JACK client. This is not necessary: the
process callback will only run after jack_activate (which is right
before the mutex is released in jack_init()), and will stop running
by the time jack_client_close returns. We don't actually need to
unregister any ports, so just call jack_client_close first thing in
deactivate_jack, which will guarantee the process callback has
completed before returning.

In fact, jack_process_callback isn't allowed to lock any mutexes or
allocate any memory at all, so this plug-in is still broken in this way
as obs_source_output_audio does that. This can cause audio xruns, as
realtime guarantees are violated. This is something that should be
fixed in the future, but at least it's not a deadlock.

Ports which do not feed audio back into JACK should be marked as terminal.
This allows latency compensation to work properly.