Resolve "Implement updating payscale"

Allows students to request a change in their payscale through raise requests.

student side

• profile page
  • added button in the side panel that reveals overlay with a form to submit a new raise request
  • added section on the bottom, that shows ongoing raise requests, if present

staff side

• raise requests page (new)
  • a table with all open raise requests, where a teacher can approve or reject them

Closes #32 (closed) #33 (closed)

Depends on !172 (merged)

Screenshots

Added button in side panel

Overlay when submitting new request

A pending request shows up in user's profile

In case a request was already submitted

Staff side: a list of pending requests