To support FTL, it needed to be present in-tree to be compiled. This PR
adds support for system-wide installations of libftl. It uses
pkg-config to find the system-wide installation. If pkg-config can't
provide libftl we just fall back to using the in-tree submodule. If
that's also not available it won't be included at all like before.

This adds a interact button to the source toolbar. It is only
shown when source is interactable.

The filters icon color was #ffffff. This changes it to #d2d2d2, the
same as the other icons.

This caused issues on case sensitive filesystems

- macOS Browser Docks
- Virtualcam Frontend Function/Events
- Manually set default font size
- Expose reload function for browser panels

Allow to load obs plugins from arbitary directory, specified by
OBS_PLUGINS_PATH and OBS_PLUGINS_DATA_PATH environment variables.

Adds ability to start and stop the virtual camera from the
system tray.

Functionality is coming in a future Windows update to disable the yellow
border when using WGC. Add code now to opt in. Will require SDK upgrade
later for OBS build.

winrt::apartment_type::multi_threaded is necessary to dodge assert for
calling get() on RequestAccessAsync result. Don't think I will ever
fully understand COM apartments.

CreateForWindow can fail if the window is destroyed.

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.