Push notifications was only ever setup to connect to Parse.com a service
that has been discontinued.  Since we haven't replaced the functionality
for a few years now, remove this dead code.

In cms/templates/js/course_info_update.underscore we're allowing content
to not be escaped because this is by design according to the tests.
Long term there should be a better fix for this but for now this is
intended behavior.

https://github.com/edx/edx-enterprise/compare/0.67.0...0.67.1

https://github.com/edx/edx-enterprise/compare/0.66.1...0.67.0

This reverts commit 23e17b3c.

References to this field were already removed with:

https://github.com/edx/edx-platform/pull/16987

We no longer need the drop_existing_session flag on IdP configurations
because dropping the existing session should actually be the only
behavior for certain view in the edx-enterprise code.

https://github.com/edx/edx-enterprise/compare/0.51.0...0.51.2

Follow up PR for PR-15863 to remove the field from database table.

LEARNER-2201

A named outer is suitable when dealing with IntegrityErrors. It only
checks that it is not nested under an atomic only if it is nested
under enable_outer_atomic(name=<name>). This way only the view which
is causing IntegrityErrors needs to have its automatic transaction
management disabled and other callers are not effected.

Please note that this is a squshed commit and the work of:
Symbolist, macdiesel, nedbat, doctoryes, muzaffaryousaf and muhammad-ammar

1 level of transactions.

TNL-367

TNL-367