Allow adjusting application font size

[droidmonkey]

• Closes Allow selecting font size  #6822
• Fix fixed font not following default font's point size
• Allow for custom offset values manually set in the config file (bounded to -2 to 4)

Screenshots

Small Font:

Large Font:

Testing strategy

Tested on Windows, may need testing on other platforms

Type of change

• ✅ New feature (change that adds functionality)

[codecov]

Codecov Report

Attention: Patch coverage is 88.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 63.92%. Comparing base (f2ed4e3) to head (864908b).
Report is 31 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/gui/ApplicationSettingsWidget.cpp	78.57%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #11567      +/-   ##
===========================================
+ Coverage    63.88%   63.92%   +0.04%     
===========================================
  Files          362      362              
  Lines        38147    38171      +24     
===========================================
+ Hits         24370    24399      +29     
+ Misses       13777    13772       -5     

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[xboxones1]

I checked in Linux, it works fine. Is more fine tuning possible? I would like to set the font size in numbers instead of four presets.

[droidmonkey]

The presets are: -1, 0, +1, +2 points offset from baseline. If you want to go down to -2 or +3 or +4, then you csv do that manually in the ini file. You really can't get more variety than that.

[NickWick13]

How about adding tiny and huge options?

[droidmonkey]

I tested this with tiny (-2) and huge (+4) during development. Tiny makes text unreadable. Huge breaks the UI. The choices presented are purposefully made.

[varjolintu]

Tested with the default values in macOS, and everything works great.