[REQUEST] Allow choose between 2 or 3 letter language tags

[MartenBE]

When asking a subtitle for movie.mp4, the subtitle will be named movie.eng.srt. I was wondering if it were possible to let it output 2 letter country codes so it would be movie.en.srt? This would allow it to work better together with tools as https://github.com/Diaoul/subliminal . The use of 2-letter codes is also more appropriate with BCP 47 [1][2]

[1] https://www.w3.org/International/questions/qa-lang-2or3 "Should I use two-letter or three-letter ISO language codes in language tags?" [2] https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry

[MBR-0001]

I believe this should be moved to the jellyfin server repo since it is the one that controls this