In TeacherClassView, when a teacher assigns a paid course to any unenrolled
student, the view automatically enrolls those students, rather than requiring
the teacher to enroll those students manually first. Update copy throughout.
Also add back (smaller) padding to progress dots in TeacherClassView.
* Refactor several related endpoints and views
* Redesign EnrollmentView, add TeacherContactModal
* Add "Enrollment Status" tab to TeacherClassView
* Delete PurchaseCoursesView and related files
* Style-flatten RemoveStudentModal
* Fix error handling in ActivateLicensesModal
* TeacherCoursesView loads faster by only loading course campaigns, and not load prepaids
