Creative Commons Licensing for edX

This PR adds Creative Commons Licensing to the Open edX Platform.

Review tickets
T&L https://openedx.atlassian.net/browse/TNL-195
UX https://openedx.atlassian.net/browse/UX-948
I'm confused why the code you've added in this file is so different than what was added in `cms/djangoapps/contentstore/views/course.py`. You need to add more comments in your code. I don't understand fully what's going on. Can you please go through your changes and add explaining that says, this is what this is doing here and why? Definitely here and in course.py, but really, you can't make too many comments. Even if you think it is excessive, I have not been developing this code with you so I don't have your knowledge or understanding.