Backbone version of the course outline page

STUD-1726
Merge pull request #4227 from edx/andya/backbonify-course-outline

Backbone version of the course outline page
Add "visible_to_staff_only" field to support staff locking in Studio.

STUD-1875
First pass at locking.
First bok choy test for visible_to_staff_only.
First cut at staff lock UI
Show the correct block color for all states