PSA was monolothic, now split, with new features, like
a DB-backed partial pipeline. FB OAuth2 version also upped.

Partial pipelines don't get cleared except when necessary.
They persist for special cases like change of browser while
still mid-pipeline (i.e. email validation step).

Refactor, cleanup, and update of a lot of small things as well.

PLEASE NOTE the new `social_auth_partial` table.

There's no need to use a string literal in setattr, delattr, or the
two-argument form of getattr.

Wrap 3rd Party Auth Pipeline with Segment enabled checks

PR #8930

ECOM-1017

* Add a new cookie for user information
* Make marketing cookie names configurable.
* Handle URL reversal when URLs don't exist (in Studio)
* Move cookie code from student/helpers.py into its own module.

TNL-2024

TNL-1535

Automatically link edX account with social account in login mobile API path

TNL-1493

See https://openedx.atlassian.net/wiki/display/TNL/User+API for details

TNL-1491

See the API design here:

https://openedx.atlassian.net/wiki/display/TNL/User+API

Users who are blocked from enrolling in a course
due to an embargo are redirected to the blocked
message page after authentication completes.

Makes logistration available at /login and /register as well as /accounts/login/ and /accounts/register/. In addition:

- Adds support for redirect URLs in third party auth for combined login/registration page
- Adds support for external auth on the combined login/registration page
- Removes old login and registration acceptance tests
- Adds deprecation warnings to old login and register views
- Moves third party auth util to student_account
- Adds exception for microsites (theming)

Fix all the 3rd party auth scenarios.

Update pipeline to preserve parameters.

Updating tests

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

This reverts commit f40447b3.

Conflicts:
	lms/urls.py

Revert "Add support for external auth on the combined login/registration page"

This reverts commit 98875339.

Conflicts:
	lms/templates/courseware/mktg_course_about.html
	lms/urls.py

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