* Commits:
  Add is_staff check to masquerade POST
  Convert masquerade view to class-based

[CRI-174] [BB-2402] Fix LTI issues due to duplicated Content-Length header

AA-115: Adding external API for dates tab

This adds in the API for the Dates Tab for use by the
Course Home MFE.

Cleaned up a few more things about the testing configuration now that we've deployed Django 2.2 to production:

* Go back to a single version of django-oauth-toolkit, tox doesn't need to vary it anymore
* Go back to PyPI release of django-method-override
* Remove no longer needed dependency on python-oauth2 (we already removed the package it was used by)
* Update prepare_xdist_nodes.sh with new Django requirements file options

Remove code from the courseware index page that was only relevant if the shopping cart was enabled.

Restrict api to staff users

Optimization

** This removes some of the extra
   celery calls to credential service for
   updating grade when a certificate is updated.

** This removes extra db calls
   by reusing existing queryset values.

PROD-1363

Update swagger.yaml, fix some markup errors

* fix query to remove dulicates and incorrect teams

importing ENTERPRISE_CUSTOMERS_EXCLUDED_FROM_CATALOG list from settings following same pattern that is used for CORS_ORIGIN_WHITELIST

[AA-139] Record schedule updates to the history table when granting e…

Only the data download tab should appear for data researchers

TNL-7222

added reverse_sql method attribute to avoid sql operation error YONK-1588

* Commits:
  Check if user can upgrade prior to showing sock upgrade

AA-159: Improving performance of get_course_assignments

It is only referenced inside of the serializers so we can just
define it there

We saw an increase in response time with recent changes to the logic
behind get_course_assignments. This effort works to better access
the information we need in order to improve performance.
Namely, this is done by using the course_blocks_api

Don't include staff-only sections in due date calculations for self-p…

Revert "Unpin django-cookies-samesite now that it declares ua-parser dep"

This reverts commit 27480a25.

highlight topic cards on tab-select
add border highlight to sorting select input on teams and topics pages.

Co-authored-by: Ben Warzeski <benwarzeski@edX-C02CD0HCLVDM.local>