UI: Remove unnecessary global variables

CI: Add Github Actions workflow for branch pushes and PRs

mac-capture: Use window id to identify windows on MacOS

CMake: Build Windows modules with file descriptors

UI: Add status icons for recording and streaming

UI: Adjust a few margins

plugins: Build ALSA plugin for FreeBSD

-Remove 9px margins around central widget. This saves 18px of vertical
space. This will be helpful when the source context menu is added,
which is 24px tall.

-Adjusts margins in transitions dock. The top of the transitions dock
wasn't lined up with the top of the controls dock, which made it look
bad.

docs/sphinx: Add Property Grouping

UI: Fix previewLabel styling

UI: Remove all scenes in ClearSceneData

obs-qsv: Enable QSV texture-based encoding

obs-ffmpeg: Fix media source not closing file when inactive

libobs: Don't save removed sources

CI: Add qt5-xml package for FreeBSD build task

linux-v4l2: Fix build with Clang 10.0

Enables a pipeline for texture-based encoding with QSV. Utilizes OBS
NV12 output for encode to avoid offloading them from GPU, which will
increase performance. The option to select old QSV pipeline still
remains and will fallback if new pipeline fails.

libobs: Fix plugin folder search path case on macOS

linux-jack: Fix conversion from channels to speaker layout

The UI feedback when dropping scene / source items on other parts of the
program indicated that something would happen instead of showing the
"no drop" icon.

UI: Fix projector on other than primary display

Calling showFullScreen after setGeometry puts the projector on the
expected monitor.  Previously (on FreeBSD, at least) it opened on the
primary display.

add_control_property() was previously static inline bool, but did not
return a value and failed to build on FreeBSD-CURRENT with Clang 10.0,
with:

error: non-void function 'add_control_property' should return a value