Replace `fullcalendar-reactwrapper`

[KindaOK]

Depends on an old version of React and is no longer maintained.

Options

• fullcalendar
  • Pros
    • most similar to what we use already
    • will probably be easy to swap in
    • default styles and whatnot are also close to what we already use
  • Cons
    • react wrapper with a ref around a preact thing
    • heavy
• react-calendar
  • Pros
    • written in react and is actual react
    • lighter
    • more extensible?
  • Cons
    • default styling is pretty different from what we have
    • will need more work to make it look and work like how we want it to

We could also probably rip out bootstrap as well at the same time since it only exists for nice default styles and is kinda heavy.