feat(admin): create student assignment workflow

[CaerusKaru]

This is distinct from the instructor assignment workflow, because we can guarantee some different concerns with students, namely:

• We don't have to manage uploads, students will do that themselves
• We do have to manage a number of additional contingencies, including submission time, exceptions, number of submissions, late penalties, group submissions, automated testing, and others

For these reasons, and for the interest of the instructors, grading setup does not take place at the same time as assignment creation (even though it's the opposite for instructor assignments). This is because setting all of these parameters may take place before grading is decided, which is generally not the case with exam uploads.

So, in no particular order, these are the elements required for this issue:

• Assignment name, optional description, optional submission guidelines (as PDF or Markdown)
• Submission dates, late submission date, late penalty, max number of tokens allowed (note: token setup is handled at the course level, not the assignment level), max number of submissions
• Files to accept, whether to restrict beyond required files, upload size limit
• Advanced options, including submission exceptions (which allow for adjustments to any of the above as a group or individually), group submissions (should this be advanced?), and TBD

[CaerusKaru]

Another potential configuration could be the inclusion of starter code, but this depends wholly on how much we want to offload the burden for course websites, which generally contain the description and content of assignments.

Should discuss with instructors on potential benefits/usefulness

[CaerusKaru]

Implemented all fields in the backend, just need to sync with frontend