[Neos] NeosDemo Localisation: remove en_US dependency

[armin otto]

ok, I couldn't fix the problem by correcting the active site, but I could fix it by editing the sites.xml file in the installer package.
I simply replaced all en_US instances with e.g. de_DE and and modified the settings.yaml file so de_DE is the only language.


Also, I can't have language dimensons that are completely independend of another. You need one root and have every language inherit from it.
Furthermore, since the demo package carousel node making problems, I removed it from the sites.xml file, which saved me a bunch of other problems.