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
So you're getting the text description from an API call? That's going to be slow, and you should document that in the docstring at least. Also, why do you need to fetch the text description? What's wrong with just including a description in the code?