Support formsets

[Confidenceman02]

Formsets are actually pretty rad. Django does some clever tricks to enumerate the forms on submission which could easily be handled by Elm.

Formsets of course render static forms which are mostly fine but if you wanted to add some fancy dynamic stuff with Elm, it would be great to take over the formset rendering.

Without thinking too deeply about it, I imagine it could be a flag class that breaks down the formset in to the pieces required to handle it in an Elm program.