Add ability to filter languages in MediaInfo formatter

[Taloth]

Database Migration

NO

Description

Definitely a 1% feature.

@markus101 We talked about this and I think it would still be better to filter by language profile or something, but I feel like there's more edgecases there and harder to implement.
Allow {MediaInfo SubtitleLanguages:EN+DE} custom format to influence formatter:

• :EN+DE filters out all except EN and DE (the order here determines the output order too)
• :-DE-NO filters out DE and NO
• :EN+DE+ (trailing + ) will replace any unlisted languages with --, so a file with EN+NL+NO would become [EN+--] (not sure about this one)

Formats work for AudioLanguages, AudioLanguagesAll and even Full. For Full it'll eliminates any possible future formatting for the codec/etc stuff that's in Full, but that's not a big issue imo.

Finally I'm also not sure about how to document it.

Todos

• Tests
• Documentation

[markus101]

Looks good.

:EN+DE+ (trailing + ) will replace any unlisted languages with --, so a file with EN+NL+NO would become [EN+--] (not sure about this one)

Maybe we should have the trailing + just indicate that there are more languages, using your example, a file with EN+NL+NO would become [EN+], but a file with EN+DE would just be [EN+DE]

[Taloth]

Problem with that is what would you do if the languages are EN & NL and the format is :DE+.
In the current format it'd be [--], leaving the hyphens out would mean either [+] or just nothing.