Add Django apps for student account and profile

Add Python APIs for account/profile information to user_api
Updating profile page to have social linking

@stephensanchez @rlucioni @AlasdairSwan Please look over these changes.  Since this is behind a feature flag, we don't need this to be 100% complete, but the functionality we've implemented so far should work correctly.
Nitpick again, would it be reasonable to split some of these functions out into something more common? such as cookie, regex, ajax? Maybe not, just thought I'd ask.