Implement "User sees 'Replay' button"

ChallengeProgressions are now posted to the server on challenge
completion. Implement ChallengeProgressions controller and route.

Initial implementation of dashboard functionality. Implement
service object for Dashboard.
Implement 'User sees completed challenges'

Implement all AC for 'User sees completed challenges' US. Implement
completed challenges section in dashboard.
[Finishes #52912279]