[Feature] Prerequisite (and Postrequisite) Tree

[btwj]

Description

In the course detail page, render a prerequisite tree. For example, for a course E with prerequisites (A or B) and (C or D), we should show something like

A --|
   one of --|
B --|       |
          all of --- E
C --|       |
   one of --|
D --| 

Clicking one of the prerequisite courses should in turn render that course's prerequisite tree.

Designs

No response

[Lhwhatever]

To be done after migration to Prisma: #100