Grade View - display and use only currently enrolled students

[AndiB]

On the Grade Summary page, I would like to be able to only see students who are still currently enrolled in the course (as well as the current functionality to see all students who ever added in the course). Maybe a toggle can filter this view.

I would also like to be able to download the grade summary with only students who are currently enrolled in the course.

I would also like to be able to see the grade statistics (according to the course marking schemes) calculated with only the currently enrolled students.