Augment TMDB tags with original language

[bradbeattie]

Changes
When generating tag metadata from TMDB, include the original language as a tag (e.g. lang-en or lang-fr).

The intent here is to piggyback on SqliteItemRepository's use of tags to determine item similarity to also consider a movie's original (primary) language. The result being that Jellyfin's "More Like This" would give some relevance to a movie's language.

Furthermore, in concert with #8842 this change would allow searching for content by language.

Issues

Partially addresses https://features.jellyfin.org/posts/39/filter-videos-by-audio-stream-language

[bradbeattie]

GitHub actions are showing a failure, though I suspect it isn't my code change but instead related to the dotnet 6->7 changes commited within the last 72 hours. I'll revisit this PR when that's resolved.

[bradbeattie]

Closed and reopened as #8916. I suspect the dotnet changes have made their way in, but I couldn't seem to find a way to kick off the Github actions again without reopening the PR.