Grader management of submissions

[pretendWhale]

When TAs have the 'manage submissions' permission, they must assign themselves as graders for each group they want to manage the submissions of. This occasionally causes confusion because the TA and/or the instructor don't know about this interaction. To make this more clear, we could do something like the following:

• By default, make roles with the 'manage submissions' permission able to view all submissions, rather than needing to be assigned as a grader.
• Create a separate permission which does the above
• Create a separate permission which allows instructors to determine whether a grader can see all submissions vs only those they have been assigned to grade.

However, this also has the potential for introducing confusion when marking, if the TA is only assigned to grade a subset of submissions. To address this we could:

• Introduce a toggle on the submissions table to toggle between showing all submissions and only submissions that the user has been assigned to grade.
• Add options for arrow navigation in the results view to toggle between only the submissions the user has been assigned to grade vs all submissions. This could also be used to add additional options: for example, allowing users to view results in a random order.

These could also be used for instructor users