Changes and updates ported from cfgov-refresh.

There's a lot of stuff we learned from cfgvo-refresh that we wanted to port to cf-demo and/or a generator like this. Let's keep this PR open until I can test this out locally though and to give you a chance to ask questions if you need to.
More info on the `cf-less` updates: https://github.com/cfpb/cf-grunt-config/pull/26