JIRA: TNL-710

IMPORTANT: this commit converts the course_groups
package to using migrations.  When deploying to an
existing openedx instance, migration 0001 may fail
with an error indicating that the CourseUserGroup
table already exists.  If this happens, running
the 0001 migration first, with the --fake option,
is recommended.  After performing this step,
remaining migrations should work as expected.

TNL-649

Move to github.txt and make editable

TNL-890

Add support for redirect URLs in third party auth for combined login/registration page

Remove old login/registration acceptance tests

Add deprecation warnings to old login and register views

Move third party auth util to student_account

Add exception for microsites

TNL-558

JIRA: MA-147

This reverts commit fb6579abfdb6fc9fb8bc9233554ff5c6e9215659.

JIRA: MA-147

If feature flag is enabled, replace the old login/registration pages with the new combined login/registration page.

- has_course_access renamed to has_course_author_access for clarity
- Changed doc string to clearly state that it determines whether or not
  a user has write access to a course

This reverts commit 61cf1d6e.

Conflicts:
	requirements/edx/github.txt

This scope offers a simple claim, administrator, that is true iff the user is a superuser.