Implement lessons in progress for dashboard

Dashboard now shows lessons in progress. Implement lessons_in_progress
method to provide lessons to view.
[#52945439]
Implement assignments in progress for dashboard

Implement 'User sees assignments in progress' AC. Implement
method in Dashboard to return Courseworks that are not completed.
[#52945439]
Implement completed assignments in dashboard

Implement method in Dashboard to return completed assignments and
utilize in view.
[#52945439]
Make challenge completion markup consistent
Implement card queue in dashboard

Implement card queue display in user dashboard.
[Finishes #52945439]