www/py-django-registration-redux: Update to 2.7

• Assign the port to Django 2.2 (current LTS release) because Django 1.11 is End-of-Life since April.

• Switch back from Github to CHEESESHOP as sdist tarballs at PyPI are available again.

• Also remove textproc/pootle from CONFLICTS_INSTALL as it no longer exists in the Ports tree.

PR: 245643
Approved by: Kevin Golding <ports@caomhin.org> (maintainer)