--------
feat: enrollment API enhancements
- Allows Enrollment API Admin to see all enrollments.
- Makes the endpoint return more fields, such as: enrollment_track,
enrollment_date, user_email, course_start and course_end.
- Changes EnterpriseCourseEnrollment's default ordering from 'created'
to 'id', which equivalent, but faster in some cases (due to the
existing indes on 'id').