I don't want ubuntu dark as this has orange color.
Instead I want the default which has blue colors.
Don't know how this happened, most parts were blue until today.
I'm still German and living in Germany.
It is strange to have Sunday as first day of week.
I configure some languages to be German, others to be English.
I also fix the wrong utf8 syntax, Ubuntu uses `utf8` instead.
Use home-manager to create xsession.
Readme contains info on how to start xsession on login.
That way home-manager can maintain languages, keyboard and further stuff
globally for user.
No more need to set stuff as workaround within i3 or zsh.
Also enabled to start systemd units after login, as home-manager will
create and trigger `hm-graphical-session.target`.