Fixes #576 High/Low DPI Adapting

The Qt UI would change the size according to the logical DPI of the computer.
Only Windows and Linux have been tested. (Should also work on Mac but have not tested).
The unit test for the new file is also added.
:memo: Improve docstrings

Make them more readable and informative.
Also fix punctuation, spelling, and grammar mistakes.

Related to #640
Added ComboBox for Quality selection
Ogg Output settings now modified by quality selection
Add Audio/Video quality saving to config. All output plugins except WebM now affected.
Added bitrate/quality customization to Ogg Icecast.
Some code changes
Added 'configurable' variable to output plugins class
Added scaling support
Moved video resolution determination to input plugins and passthrough plugin
Quality disabled for non-desktop sources
Removed redundant config loads
Removed config load checks for plugins that don't need it
Fixed config test and loading of avWidget
Modification to test
Some more efficiency improvements
Changed audio/video quality at record time; Added custom field to quality
Removed unnecessary variables and arguments
Added docstrings
Moved bitrate/quality config to separate dialog
Disable quality options when no output is configurable