Incorporate django-all-auth (social login)

[readytheory]

For commenting, or to allow a multi-author site, there needs to be some login method.

Django comes with a User model but don't want to use that unless it is a prerequisite for social login.

Requirements for this feature need to be clarified:

• site owner should not be involved in issues like lost password
• site owner should not collect any data about commenters

This is a large issue that will require resources to test and need refinement of scope.