New Grader: time assignment submitted

As the new grader is being built, I wanted to mention that teachers are requesting a way to easily tell whether a student submitted an assignment on time or late. I know each interaction is time stamped, but the teacher cannot see these without digging, and they don't want to look at each exercise. Most LMSs have a submit button for assignments that is timestamped so that you know whether they did it on time.
In the new grader, there could be a time submitted field that is shown in the grader page. This could be the time that they changed the status of the assignment from In Progress to Finished, or it could be the last time they interacted with any exercise in the assignment. It could show in green for those on time and red for those that are late.

The issue names no file, test, or entry point; first locate the new grader implementation and clarify which event defines submission and how assignment deadlines are obtained. Done should mean the grader page shows a submission time and clearly indicates whether each assignment was on time or late.