ECOM-4214

More accurately, this creates a 4th shard because the
last shard is always the default.

More accurately, this creates a 4th shard because the
last shard is always the default.

The verification workflow assumes that all verified courses will have a
price. Free verified course modes cause a 404 when the user attempts to
enroll or upgrade.

Available backends:

* django-oauth-toolkit (DOT)
* django-oauth2-provider (DOP)

* Use provided client ID to select backend for
  * AccessToken requests
  * third party auth-token exchange
* Create adapters to isolate library-dependent functionality
* Handle django-oauth-toolkit tokens in edX DRF authenticator class

MA-1998
MA-2000

FEDX-24

Allows staff users to manually enqueue the task responsible for awarding programs certificates. ECOM-3692.

This brings the enrollment support tool's UI in line with the other
support tools.

Allows support staff or global staff to view a list of a learner's
enrollments, and change enrollment modes. We generate a
ManualEnrollmentAudit record for these enrollment changes in order to
track updates. Additionally, enrollment changes are handled through
the enrollment API, which handles bookkeeping such as granting refunds
where appropriate.

ECOM-2825

Allows support staff or global staff to view a list of a learner's
enrollments, and change enrollment modes. We generate a
ManualEnrollmentAudit record for these enrollment changes in order to
track updates. Additionally, enrollment changes are handled through
the enrollment API, which handles bookkeeping such as granting refunds
where appropriate.

ECOM-2825

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

* Add new role for support staff.
* Move dashboard/support functionality into a new Django app called "support".
* Add support view for searching and regenerating certificates.
* Refactor certificates views into separate files.