Lyrics: Resurrect translations and refactor ReST and command line handling

[snejus]

🎵 The Refactoring Blues 🎵 by Claude

Verse 1:
Got those lyrics plugin blues
Cleaning up some messy code
Moving classes, fixing views
Making changes down the road

Chorus:
We're refactoring tonight
Making the codebase clean and bright
Translation's got a brand new home
And ReST files found their own

Verse 2:
Added Microsoft Translate
Keeping tokens safe and sound
Config options up-to-date
Better structure all around

Bridge:
Path operations simplified
Groups of artists, neat and tied
Error handling's looking fine
Comments clear along each line

Verse 3:
RestFiles in their own class now
Cleaning imports, showing how
Better typing makes it clear
What should go and what stays here

Final Chorus:
We're refactoring tonight
Making the codebase clean and bright
Translation's got a brand new home
And our code can stand alone!

— inspired by the diff

---

Technical Changes

• Replaced deprecated and broken Bing translations by Microsoft Translator API

  • Isolated all functionality in the Translator class.
  • Updated translation settings configuration.
  • Added support for synced lyrics from LRCLib.
  • Added support for preserving existing translations to help users to manage their characters quota.
  • Added error handling and logging
  • Added tests

• Created RestFiles class for ReST document handling

  • Simplified path operations using pathlib
  • Added tests

• Improved command line options handling

Caching of translations

The plugin will not re-translate lyrics if translations already exist, see

$ beet -v lyrics albumartist::Sel karta -f
...
lyrics: LyricsPlugin: Fetching lyrics for Sel - Saulės Miestas
lyrics: LRCLib: Fetching JSON from https://lrclib.net/api/get
lyrics: LyricsPlugin: 🟢 Found lyrics: 32275 | 1996 / Neįvertinta Karta: Sel - Saulės Miestas
lyrics: Translator: Posting data to https://api.cognitive.microsofttranslator.com/translate
lyrics: Translator: 🟢 Translated lyrics to EN

$ beet -v lyrics albumartist::Sel karta -f
...
lyrics: LyricsPlugin: Fetching lyrics for Sel - Saulės Miestas
lyrics: LRCLib: Fetching JSON from https://lrclib.net/api/get
lyrics: LyricsPlugin: 🟢 Found lyrics: 32275 | 1996 / Neįvertinta Karta: Sel - Saulės Miestas
lyrics: Translator: 🔵 Translations already exist