Allow Auto Translate to Use Other Services

[graywolf336]

Currently the auto translate functionality only utilizes Google Translate for the auto translating, however there are other services out there. Ideally we would make this pluggable somehow, possibly with the upcoming Rocket.Chat Apps, #6890.

cc: assistify#175

[janrudolph]

@graywolf336 We now have to integrate Microsoft Translator as well. Do you have any ideas for a pluggable, general architecture? Otherwise we would start to implement it like DeepL

By the way:
I added two different issues for the translation:

• Add Microsoft Translator as translation service assistify/Rocket.Chat#623 (adding Microsoft Translator)
• Using different translation services simultaneously  assistify/Rocket.Chat#624 (Using different translation services simultaneously)