Implement issue submission

[v-pan]

A form to submit issues.

Frontend (design on Trello):

• Input boxes for:
  • Issue title
  • Description of issue
  • Resolution criteria
    • Severity
    • Category

Backend

• Integrate into current Firestore implementation

[v-pan]

Currently no authentication for content submitted to the Firebase. UID checking should be easy, but the content is still pushed from the client side, which is undesirable