Reruns/cms server side LMS-11016

This PR is an updated version of this old one: https://github.com/edx/edx-platform/pull/4573
I had kept the `course_id` name consistent with the naming convention in the rest of this file.  Is there a platform-wide effort to change it to `course_key`?  I wasn't aware of that.  Since we still support the `course.id` method, `course_id` also makes sense.