maniacs-setup does not define MAAS "spaces"

Somewhere along the line, MAAS began relying on network "spaces." Currently, maniacs-setup does not define these, leaving both internal and external networks on "undefined" spaces. This seems to work, although there's an alert in the MAAS networks page about this fact. We should probably adjust maniacs-setup so that it defines two spaces, one for the internal and the other for the external network, and assign them properly.