[SIS] Filter out past synced grades in grade sync window

[AOverby]

Problem statement:

The grade sync window shows every synced and unsynced assignment. As you progress through the school year, the list of assignments in that window gets long as past assignments that have already been synced continue to show.

Proposed solution:

Add the ability to set a filter in this window so that teachers can set it to show only assignments from that grading period. Or, give them the ability to hide/unhide previously synced assignments. This will be a time-saver for teachers and reduce the "clutter" when syncing.

User role(s):

admin,instructor