Add ability to set staff lock from course outline

STUD-1851. @cahrens please review.

Sandbox available at http://studio.benmcmorran.m.sandbox.edx.org/course/edX/Open_DemoX/edx_demo_course
Why can't containerPage.model.get('has_inherited_staff_lock') be used (or staff_lock_from or one of the other related variables) instead of having to pass in keepImplicitStaffLock?