Updating the design of the DRF views for enrollments.

Consolidate PUT and POST on the RESTful Layer.

Change URLs for API

Test cleanup.

Adding a course details URL to the enrollment API.

Change student to user

Change to v1, remove feature flag from API URLs

Updating student to user in tests

Re-ordering redirect urls to be evaluated last.

Adding pagination and testing.

Adding Django REST settings for pagination.

Revert "Re-ordering redirect urls to be evaluated last."

This reverts commit 4c9502daa383e49b46f8abec5456c271e5e24ccb.

Re-ordering redirect urls to be evaluated last.

Conflicts:
	common/djangoapps/enrollment/urls.py

Revert "Adding Django REST settings for pagination."

This reverts commit 9f8a54c41f34caa24818c88f1e75ac59f6ce5259.

Conflicts:
	common/djangoapps/enrollment/urls.py

Revert "Adding pagination and testing."

This reverts commit 0b2d46262abb78f5ad170700205e7fd28b6af942.

Additional testing, logging, and error messages.
Merge pull request #6216 from edx/sanchez/cleanup-restful-layer

Enrollment API Cleanup