Implementation for DE-1089. Centralize the definition of context into a single method. This is in common/djangoapps/track because the context is originally set there by middleware.
The ``user_authn`` app contains user authentication related features such as login and registration. * Ideally this would be in its own service, but at this point, LMS is the home of all authentication related features. * At this time, these features are still plugged into Studio. Future clean-up in Studio is intended to make this an LMS only feature.