Replace LibreTranslate detect server call with Apple's Natural Language library

[tyiu]

https://developer.apple.com/documentation/naturallanguage/nllanguagerecognizer/2976557-dominantlanguage

Makes it slightly more performant by decreasing the max number of required server calls by 1 per selected note.

Also seems to be more accurate in language detection. Which means some of the Chinese posts we've been seeing are actually being detected as Chinese properly.