- API built atop Django REST Framework
- Added support for OAuth 2.0 and session authentication
- Added permissions around eligibility data

ECOM-2609

The update (PUT) endpoint now supports creating new CreditCourse objects in addition to updating existing ones. This functionality greatly simplifies the logic needed by consumers (e.g. the Course Administration Tool) to create or update CreditCourse objects.

ECOM-2524

ECOM-2538

* Upgrade edx-submissions
* Upgrade edx-ora2
* Upgrade edx-val
* Upgrade edx-proctoring
* Update all edx-platform code that depends on DRF, including:
  - auth_exchange
  - cors_csrf
  - embargo
  - enrollment
  - util
  - commerce
  - course_structure
  - discussion_api
  - mobile_api
  - notifier_api
  - teams
  - credit
  - profile_images
  - user_api
  - lib/api (OAuth2 and pagination)

* Upgrade edx-submissions
* Upgrade edx-ora2
* Upgrade edx-val
* Upgrade edx-proctoring
* Update all edx-platform code that depends on DRF, including:
  - auth_exchange
  - cors_csrf
  - embargo
  - enrollment
  - util
  - commerce
  - course_structure
  - discussion_api
  - mobile_api
  - notifier_api
  - teams
  - credit
  - profile_images
  - user_api
  - lib/api (OAuth2 and pagination)

Floating point values should be treated as strings to ensure values such as 1.0 are not converted to 1. Such conversion invalidates the signature generated for the credit request. Additionally, JSON has no concept of a floating point datatype.

ECOM-2172

CSRF protection needs to be disabled so that requests made using OAuth and other non-session-based authentication mechanisms can be properly processed. If session authentication is used, DRF will enforce CSRF protection.

XCOM-524

Endpoints support create, read, and list operations.

NOTE: This commit also includes a retrofitted SimpleRouter that supports overriding the lookup regex. This retrofit is simpler to implement than updating edx-ora2 which is pinned to DRF 2.3.x.

XCOM-524

ECOM-1858

Use the number of seconds since the epoch (Jan 1 1970 UTC)
instead of an ISO-formatted datetime string.  This is easier
for credit providers to parse.

* Add end-point for initiating a request for credit from a provider.
* Add an end-point for a provider to update the status of a request (approved / denied).