Better Language Support - Detect language upon post and add language tag

[rabble]

For Nostr to grow, users need to be able to find the content they want to see in languages they speak.

Nostr has a tag which can be added to any note for the language:

https://github.com/nostr-protocol/nips/blob/master/32.md

We should run a quick language detection check when posting and add this tag.

https://developer.apple.com/documentation/naturallanguage/nllanguagerecognizer

Once we start posting language tags for out content we can work on filtering by language on requests to relays.