Add formset_as_fieldsets template and tests

This creates a partial template which allows for ease of
rendering formsets. The template outputs the management
form, and wraps each form in a div with appropriate form
prefix class attributes.
Also, these `formSetForm` divs are not selectable as a group.  Having a container div would allow us to do something like this:

```css
.formSet.badge .formSetForm {
   /* Styles */
}
```