Add tr. engine LibreTranslate

[jerry-ne]

Is your feature request related to a problem? Please describe.
It would by nice to increase user privacy to using LibreTranslate engine (https://libretranslate.com/). It is possible to download and run self-hosted.

Describe the solution you'd like
Add LibreTranslate to Your Translate engines option. Provide offer online and offline (=self-hosted version).