Consider integrating with Mozilla Transvision

It might be useful to provide integration with [Mozilla Transvision](https://transvision.mozfr.org/) as a machine translation service. It provides access to all Mozilla translations.

There is an [API](https://github.com/mozfr/transvision/wiki/JSON-API), but I was not able to find usage terms for the service, so that would have to be clarified if we can use that.