Add py-dj22-django-formset-js-improved 0.5.0.2

This is a fork of django-formset-js that adds support for reordering and nested
formsets.

A wrapper for a JavaScript formset helper.

WWW: https://github.com/pretix/django-formset-js

• While I'm here:
  • Add LICENSE_FILE
  • Fix USES=python

PR: 239050
Submitted by: Alexander Sieg <alex@xanderio.de>