PROD-1045 Update the edx-proctoring library to version 2.2.7 for Email Message update. We want to update the message so we can support our course team better

Upgrade ORA to 2.6.12 | When fetching file URLs from keys stored in Submission records, don't break just because we encountered one missing file; there might be more, existing files after it.

* Removing deprecated rest_framework_oauth library

* removing dependecy of django-rest-framework-oauth

* removing oauth_provider from cms

This reverts commit 1f32bc63.

* 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

Upgrade django-toolbar.

https://openedx.atlassian.net/browse/BOM-1036

* Updating Python Requirements

* Constrain edx-when version for now

-Updated middleware setting to use use middleware insted of
middleware_classes
-github install of django-method-override fork to support
new style middleware in django1.11

Some tests that used to mock the cache internals of ConfigurationModels
had to be modified to use CacheIsolationTestCase instead (the things
they were mocking no longer exist).

Fix constraints to not have a lingering pin on edx-when. And
add constraint on version of mock that supports python 3.5.

And then a general make upgrade.

* Bumping edx-enterprise version

* Running make upgrade to bump edx-enterprise

* contraining a package

* fix

* adding yet another constraint

Updating the django-rate-limit requirement.
updated the django-ratelimit to use unreleased version that supports Django 2.2