style: add Sonar and StyleCop Analyzers

[ReenigneArcher]

Description

This PR adds SonarAnalyzers.CSharp and StyleCop.Analyzers. I mostly followed this blog post (https://dev.to/srmagura/c-linting-and-formatting-tools-in-2021-bna). They use VS Code, but everything there works in Rider just as well.

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

Branch Updates

LizardByte requires that branches be up-to-date before merging. This means that after any PR is merged, this branch
must be updated before it can be merged. You must also
Allow edits from maintainers.

• I want maintainers to keep my branch updated

[codecov]

Codecov Report

Merging #177 (4b90e08) into master (8f162a5) will decrease coverage by 0.20%.
The diff coverage is 25.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #177      +/-   ##
==========================================
- Coverage   39.08%   38.88%   -0.20%     
==========================================
  Files           4        4              
  Lines         197      198       +1     
  Branches       12       11       -1     
==========================================
  Hits           77       77              
- Misses        116      117       +1     
  Partials        4        4              

Files	Coverage Δ
Jellyfin.Plugin.Themerr/Api/ThemerrController.cs	0.00% <ø> (ø)
Jellyfin.Plugin.Themerr/Plugin.cs	0.00% <0.00%> (ø)
...yfin.Plugin.Themerr/ScheduledTasks/ThemerrTasks.cs	0.00% <0.00%> (ø)
Jellyfin.Plugin.Themerr/ThemerrManager.cs	52.73% <37.50%> (-0.37%)	⬇️