[Gradebook] Create toggles out of Gradebook filters

[Steven_S]

Problem statement:

Gradebook filters allow instructors to select a sub-set of assignments to view. However, the button created by the filter is only there to turn it off. Once used, the button disappears, and the filter must be re-selected from the drop-down menu

Proposed solution:

Allow the button created by the filters to remain as a toggle that turns the selected filter(s) on and off. Once created the selected toggle should exist as a setting of the course, so that it can be used on future visits unless intentionally removed.

User role(s):

instructor