MonitorControl v4.0.0-beta2

@stiiveo

The new v4.0.0 version is already available as Release Candidate. We encourage you to try the new version instead of the beta version and give your feedback! You should download this older beta version only if you have issues with the Release Candidate!

Changes compared to v4.0.0-beta1:

Added Internet Access Policy
Don't relinquish control over brightness keys with no external display connected if fine brightness OSD scale is active
Changed icon order in menu (when icon mode is enabled)
Gear shape icon is used for preferences + stands a little bit apart to help user focus.
Changed default to a minimum software dimming of 15% for safety reasons.
Added advanced option to enable zero brightness with software dimming.
Added 'Avoid gamma table manipulation' option for coexistence with f.lux.
Set relevant options to disabled when keyboard control is disabled.
Added Command + Q shortcut in menu when it is in standard text mode (not icon mode).
Made preferences more spacious + more room for verbose languages

Register DDC command touched status. When write on startup enabled, apply only touched command values.
Reorganised PrefKey list to be less confusing.
Disengage custom shortcut keyboard after 100 key repeat to prevent possibly endless loop if keyUp event never arrives due to any circumstance.
Fixed text for external display brightness control keyboard shortcut.
Fix cumulative darkening bug upon toggling 'Disable dimming as fallback'.
Make sure that key repeat speed for custom shortcuts do not go below a certain threshold.
Fixes text clipping issues for various languages
Added beta channel update backend
Fixed layout issue at brightness custom shortcuts.
Fixed custom key shortcuts going runaway when menu was opened during a key repeat streak.

Some preference panes may not fit to low resolution screens (1280x800 or less) in Advanced mode.

This is a beta release. If you encounter any issues, you can try the last stable release v3.1.1 or the previous beta.
If you are new to v4.0.0, please take a look at the changelog of v4.0.0-beta1 for the list of major new features!
If you discover issues, make sure to report them in the linked release discussion or in a new issue.
If you want to help translating, see #637
Thanks to everyone who helps make MonitorControl better!