TVDB covers TV far better than the existing sources, so add it as a
provider and let users decide where it sits in the lookup chain.
- new TVDB v4 provider: search, get_by_id, get_external_ids and
find_by_imdb_id, with a process-level token cache and 401 re-auth
- metadata_providers config both orders and filters the providers used,
so TVDB can be primary rather than a TMDB fallback. Cross-validation
keeps its own fixed trust ranking, unchanged by search order
- --tvdb-order renumbers episodes into a TVDB season order. A service
does not always use aired order, so the source order is detected
rather than assumed, and the renumber is refused when an order that
omits episodes would give two of them the same filename
- --tvdb sets the series ID directly, skipping the lookup
- the Matroska TVDB2 tag now populates on every lookup path, including
--imdb, which previously produced no ID tags when IMDxAPI was off
Search matches on year as well as title so an identically named remake
cannot win on title alone.
imSp4rky