Support Domain Language Access

This patch requires also a patch 🐛 Update overrider context every time Needs review for the Domain Language Access module itself.

Hi Alex,

I have a rewrite for version 3.0.0-beta1.
It did not work correctly when I removed the mentioned patch. That other patch results in drush not working anymore.

I completely rewritten the patch. The correct languages for the domains were not used. Instead all translations were loaded. Now I reset the language property to match the languages for the domain (and reset it at the end of the generate method).

@joeren dost, why do we need the "getAlternateUrlsForTranslatedLanguages" method?

I created a MR based on #2, but for 3.0.x.