[WIP] - Fixing NGINX tests

New attempt to complete NGINX support. Please consider this is a WIP. I'm aware I've to fix doc e probably some CS
this seems related to https://github.com/FriendsOfSymfony/FOSHttpCacheBundle/pull/148 and is not a nginx specific problem, the same applies for varnish too.

i am not sure whether we should prevent the situation here. if somebody has his custom configuration that ignores the domain, this might still work.