* chore: Update Python requirements via pip-tools. Needed the newest
edx-django-utils version.
* refactor: Use the newly-added ReadOnlyAdminMixin from the updated module and
remove the existing implementation.
* fix: edx-platform now has a Django proxy model - CourseOutlineRegenerate.
Without this fix, the permissions to the model's admin interface cannot be
added to a group and successfully granted to users.
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.
