Addition/removal of students/participants from a course

[gravitz]

Ability for teacher/administrator to add and/or remove a student/participant from a course.

[mikedawson]

Teacher/administrator can already enrol a student/participant into a course. Enrolments have a start date and an end date. This structure was setup in 2018/19ish to accurately handle cases where students dropout, return, dropout etc.

An enrolment can be ended by the teacher. This enhancement doesn't fit into any of the existing milestones, but after those are completed, we might consider adding a quick action button for the teacher to end an enrolment.