Move Horizon to / and make it work in the first place.

Having the dasboard in /dashboard doesn't feel right, especially
since there is no automatic redirect when people browse to the ip or
hostname. Which would be a natural first try. Moving to / now to make
the process behave in a simpler fashion.

Because of a packaging error the js/css wouldn't load properly, next
to that there is an issue with a supposed missing 'manage.py
compress' run. This is handled through Kolla now as well (for the
time being).
There is another supposed bug in packaging that makes webfont.ttf
return a 404. This is because of a missing alias for /static stuff,
and with moving the whole thing to / this gets adressed as well.

Change-Id: I64cd7c9effad6cf9ec7c6a41f34e1184640c8adc