refactor!: move project to standalone version

[ReenigneArcher]

Description

This is the initial migration from the Plex plugin version to a standalone version. There will likely be many bugs and things to work out after this is merged.

The initial motivation for this change was https://forums.plex.tv/t/important-information-for-users-running-plex-media-server-on-nvidia-shield-devices/883484 but there can likely be benefits of using this approach down the road, with a couple of drawbacks. The biggest drawback is the plex authentication will not be automatic anymore.

TODO:

• migrate everything to python3
• migrate everything to standalone
• add new config options since we can't piggy back of Plex server's build in authentication
• add ability to migrate existing installs to standalone
• unit test
• code coverage
• change docs theme to furo
• update documentation
• A LOT more...

Screenshot

Issues Fixed or Closed

• Closes feat: add Plex authentification #229
• Closes New Crowdin updates #525
• Fixes Unable to download the music #490

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

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud