Integration of Cirrus in Forms using formica

Refs #86 (closed)

To be fair, this is not exactly an apple to apple comparison with !26 (closed) but it's quite close.

I prefer this more simplistic approach, and I'll try to dig a bit deeper (custom layout, etc).

I eventually copied all the templatetags from formica directly in our project because I need to submit a couple of pull-requests prior of being able to use it as a regular dependency.