Fetch rosters for segments (courses and sections)

[marcospri]

Currently we fetch the roster information for course and assignments via the LTI1.3 names and roles API.

However for assignments that use segments (sections or groups) we don’t know how the students are divided across the different segments.

Fetch the full list of students that belong to each segment using the proprietary LMS APIs. As this depends on the LMS API the solutions will be different for each segment/LMS combination.

We’ll start with the most common segment type, canvas groups and repeat the process for the rest.