feat: Enhance MusicBrainz integration and improve data handling #10

- Updated Release struct to include optional fields for artist credit, track count, and release group.
- Introduced ReleaseGroup struct for better organization of release data.
- Modified scrobble function to utilize MusicBrainzClient passed as a parameter, improving dependency management.
- Implemented search_musicbrainz_recording function to streamline MusicBrainz recording searches and handle errors gracefully.
- Enhanced caching mechanism for MusicBrainz responses to reduce redundant API calls.
- Improved query construction for MusicBrainz searches to include status filtering.
- Added tests for MusicBrainz client and release selection logic to ensure reliability.
- Refactored artist credit handling in Track conversion for better safety and clarity.
- Updated dependencies in Cargo.toml for improved functionality and testing capabilities.

- Updated Release struct to include optional fields for artist credit, track count, and release group.
- Introduced ReleaseGroup struct for better organization of release data.
- Modified scrobble function to utilize MusicBrainzClient passed as a parameter, improving dependency management.
- Implemented search_musicbrainz_recording function to streamline MusicBrainz recording searches and handle errors gracefully.
- Enhanced caching mechanism for MusicBrainz responses to reduce redundant API calls.
- Improved query construction for MusicBrainz searches to include status filtering.
- Added tests for MusicBrainz client and release selection logic to ensure reliability.
- Refactored artist credit handling in Track conversion for better safety and clarity.
- Updated dependencies in Cargo.toml for improved functionality and testing capabilities.