Add possibility to set the translation domain to false

[gremo]

Same as #1852 that was closed a long time ago without a real answer.

It's unclear why we can't disable translations completely. It would be nice to set up a really fast CRUD without dealing with translations when we know that only one language is spoken.

I don't know if it's possible because I haven't dug into the source code, and I've been using this bundle for only a few weeks. It would be nice if:

• EA translations remain the same (translated) strings
• We can call setTranslationDomain(false) and have all fields, labels, and forms untranslated, without hundreds of warnings in the Symfony toolbar