Allow LLM providers to serve as translators for the discourse-translate plugin

[sam (Sam Saffron)]

This is completed now @elmstedt , see:

Content Localization and Automatic Translations for Your Community

[Meta localized to Japanese] Content localization and automatic translations are now ready, bringing multilingual support to your communities. This feature is enabled here on Meta. Our experiments here have drummed up quite a lot of buzz as we’ve been tinkering away, and we are very pleased to say that the anticipation is finally over and you can now have these great new features live on your sites too. With these powerful new additions, you can now …

We are still improving the feature, recently @nat added indexing support to Google for multi lingual communities

@keegan is working on UI to see translation progress.