Course and due date on HRM training completions

GET /v1/hrm/events and GET /v2/hrm/events now include course_id, course_name, assignment_id, and due_date on training_completed events. A campaign with several courses has one distinguishable completion event per course.

due_date is the assignment due date. When the assignment has no due date of its own, it is the campaign end date. Other actions leave these fields empty, including training_accessed, which is recorded once per campaign delivery. Completions recorded before this change also leave them empty.