Syllabus collection

[georgiashay]

Adds the ability to collect and view class syllabi. Still in earlyish stages of development.

Potential issues:

• How to handle multiple syllabi uploaded for the same semester? Currently the admin would just have to choose whether to accept only one or multiple, and it's not clear whether to display multiple syllabi if the syllabus for some semester has had multiple different versions.
• If the system is used as hoped, there will be many many syllabi for admins to review. In many cases it will be easier/faster to review syllabi compared to requirements list edit requests, but due to volume may still be significantly more work than before.
• Potential for abuse - since people can upload any pdfs they want, there is potential for uploading things that are not class syllabi. The syllabi go through the same review process as the requirements lists do, but that doesn't stop people from uploading tons and tons of spam (or worse, creating a bot to do this) and ultimately creating too much work for admins.