Create app

Create django application providing annotator-storage functionality.

https://openedx.atlassian.net/browse/TNL-780
Ah, after some discussion on our dev list, it looks like indeed, 120 is the limit. (We were enforcing it with a different config file.) So, apologies...using .pep8, and using it to ignore the char limit is consistent with platform. I take back all my comments!