docs: various updates

[ReenigneArcher]

Description

Sync with Sunshine as much as possible, see: LizardByte/Sunshine#2932

We are adding a new submodule to standardize doxygen docs in the org: https://github.com/LizardByte/doxyconfig

Screenshot

Issues Fixed or Closed

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.85%. Comparing base (3d584f0) to head (0fbfac6).
Report is 22 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #79   +/-   ##
=======================================
  Coverage   93.85%   93.85%           
=======================================
  Files          34       34           
  Lines        1839     1839           
  Branches     1023     1023           
=======================================
  Hits         1726     1726           
  Misses         49       49           
  Partials       64       64           

Flag	Coverage Δ
Linux	89.67% <ø> (+0.30%)	⬆️
Windows	93.79% <ø> (ø)
macOS	69.38% <ø> (ø)

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