Auto-translate messages in a different language (via google translate)

[braid-sync]

A task for new Braid contributors.

Goal:
When a message is sent in non-English (for now), show a translation of the message below the message.

Potential extensions (for a separate PR):

• detect the language of the user's browser, use that as the 'default don't translate language'
• for other languages, show translations, but also show buttons: for example... 'always translate Russian', 'never translate Russian' (which would store that preference)

Notes:

• this should be implemented as a separate module
• translation can be done via an external API (microsoft? https://azure.microsoft.com/en-us/pricing/details/cognitive-services/translator-text-api/?cdn=disable)
• language detection should be done locally (either braid server or client); there are a few language detection libs available:
  https://github.com/optimaize/language-detector
  https://stackoverflow.com/questions/3227524/how-to-detect-language-of-user-entered-text
• braid.core.api/register-footer-view! can be used to display content after a message