UI: Convert remux path separators to OS native style

Fixes #2272

Use volume textures for LUT filter

Add t-bar to studio mode

Co-authored-by: NJim <obs.jim@gmail.com>

Allows the ability for manual transitioning to smoothly flow
(interpolate) to the intended transition point over a short period of
time rather than simply setting a hard transition point number.  Doing
this allows manual transitioning to occur more smoothly, and in a more
visually pleasant way.

Allows the ability to manually specify the transitioning point so the
user can transition at a custom rate, usually done by a device that can
be used as a T-bar
Co-authored-by: NJim <obs.jim@gmail.com>

UI: add option to show all sources to adv audio dialog

Allows the ability to see whether an audio source listed in advanced
audio properties is currently active or inactive (i.e. in an inactive
scene)

Allows the ability to modify the properties of inactive audio sources
which may in scenes other than the one that is currently active.

Makes the function usable outside of just window-basic-stats.cpp.

Not sure what effect black_and_white.png is going for. Add grayscale.png
to try to make it clear that the other image shouldn't be used for
desaturation.

deps/obs-scripting: Expose matrix3 & 4 to scripting

Various functions available in the scripting API aren't usable
currently since you can't create the matrix3 and matrix4 needed
for their arguments.

UI: Add option to use percent instead of dB

libobs-d3d11: Increase the frame queue capacity

Sometimes Present stalls are seen when multiple swap chains are active.
This seems to fix that.

obs-ffmpeg: UI and back-end for obs-encoded streaming over various protocols such as SRT

linux-v4l2: add support for controls

Video4Linux exposes controls for capture devices.  This commit adds
those controls to the properties window for v4l2-input devices.

CI: Fix QtNetwork in Mac packaging script

Simplifies shader calculations. Not much perf gain, but GPA shows
bottleneck shift from Shader Execution to Sampler as expected.

Also fix some mip calculations along the way.

UI: Ensure OBS launches when theme is missing

This change makes it so OBS will still launch even if a theme is
missing. This change also deprecates the "CurrentTheme" config key, and
is replaced by "CurrentTheme2".

This is because a previous change to make sure OBS fell back to the
System theme in case of a missing theme had been accidentally removed.
Changing the key prevents a new version of OBS setting a theme that
doesn't exist in an older version, which would prevent that version from
launching.

obs-qsv: Add all target usage options

Using terminology from FFmpeg reference, implement:
https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/cloud-computing-quicksync-video-ffmpeg-white-paper.pdf

rtmp-services: Add YouStreamer

(This commit also modifies the UI module)

CI: Fix error deleting QT network framework on OSX

CI: Fix mbedtls id in mac deploy script

obs-ffmpeg: Enable VAAPI Rate Control

libobs: Null check hotkey device on macos