- Actually make serverfeatures partial
- Navidrome: only set multiple structured lyrics if extension exists
- Navidrome/Subsonic: minor type checking of OS extension (Navidrome implementation detail)
- Jellyfin: add separate knob for lyrics. Note, this should also probably be behind some version check...
Resolves#50. Adds a new set of components for fetching similar songs
from the current playing song. For Jellyfin, use the `/items/{itemId}/similar`
endpoint (may not work well for small libraries), and for Navidrome/Subsonic
use `getSimilarSongs`. _In theory_, this component can be used to get similar
songs anywhere.