This adds a dedicated `AvailableLanguages` struct in preparation for a more cabable language matching based on a given language config. No functional changes, just shuffling some code around for this round. Also made the LanguageMatcher non-cloneable in favor of wrapping it in an Arc, since cloning is rather expensive for this and having a reference is sufficient in all cases right now. Release Notes: - N/A --------- Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>