Handle this change appropriately in CourseModeFactory.

Also fixing Meta class being defined twice in one model

The oauth2.enforce_jwt_scopes waffle switch was added temporarily for
the rollout of jwt scopes. This removes the toggle and replacing code
with the equivalent of `oauth2.enforce_jwt_scopes` as True.

* Renamed OAuth2Authentication to BearerAuthentication
* Added back OAuth2Authentication name
-there are libraries such as edx-enterprise that still import OAuth2Authentication.  The OAuth2Authentication class should be fully removed when everything is importing BearerAuthentication correctly

- Removing deprecated auth classes
- Replacing OAuth2AuthenticationAllowInactiveUserDeprecated with OAuth2AuthenticationAllowInactiveUser
- the old class was a child class of a deprecated class that we are removing and replacing.

* Added new auth class

- Created new class called OAuth2AuthenticationAllowInactiveUser, which replaces old class with same name
- Renames previous  OAuth2AuthenticationAllowInactiveUser to  OAuth2AuthenticationAllowInactiveUserDeprecated
- Replaced all imports of  OAuth2AuthenticationAllowInactiveUser to call deprecated class instead
- testing new class in discussion(added flag based on django setting)

This adds request caching to the following places:
* course expiration wrapper (displayed in Units)
* offer banner generation (displayed in Units)
* get_enrollment
* user_by_anonymous_id
* youtube_disabled_for_course

On a sample course with edx-val enabled, this reduced the queries
for a large sequence from 450 to 155.

This will remove imports from __future__ that are no longer needed.

https://docs.python.org/3.5/library/2to3.html#2to3fixer-future

https://docs.python.org/3.5/library/2to3.html#2to3fixer-asserts

This helps out the Verified Only case where the user
is not first enrolled as an audit learner.

The previous behaviour of using a variable causes Django to complain
about changes not reflected in a migration when the default course
mode slug is changed.

staff should be able to regenerate certificates for the students
who have already earned the certificate using honor mode

Prod-612

REV-705

* Fix type mismatches in the course_modes migrations

* Fix type mismatches in the course_action_state migrations

* Fix type mismatches in the schedules migrations

* Fix type mismatches in grades migrations

* Fix type mismatches in video_pipeline

* Fix type mismatches in api_admin

* Fix mismatches in credential migrations

student: Explicitly Set fields to unicode to avoid migration

REV-980

This reverts commit 059b6197.

REV-980.
* moved get_first_purchase_offer_banner_fragment to Discounts utils.py
* added banner wrapper method
* updated banner with time limit 

Mixing byte and unicode strings causes migrations to fail.

Updated __unicode__ to __str__

python3 compatibility

assertItemsEqual with six.assertCountEqual

This reverts commit 3d261798.

The change was not quite right because the method six provides needs to
have `self` be passed in as well.  See the docs here:
https://six.readthedocs.io/#unittest-assertions

Reverting for now and we can fix it in smaller chunks later.

* REVMI-354 Add enroll_in_course permission

* Fix test

Currently, enrollment support tool is only allowing support members
to change course enrollment only one of the two modes i.e. audit and
verified.To move a learner other than these modes,they need to ping
devops.To broaden the scope of enrollment support tool,changes have
been done so that enrollment would be changed to other modes as well.

PROD-305