Recollect submissions while maintaining previous grading state

[donny-wong]

Context:
When recollecting previously collected submissions, and if these submissions have been graded, it will be overwritten. For remark requests, the recollecting will remove the remark request message itself as well. It will be helpful for a variety of reasons, to retain the remark request message, previous grading and test run information.

Proposed solution:
In the Submissions table, display a list of the current and all past grading results for a given group for an assignment. Each of these results will be a link to a grading view.