Webshop ticket scanning/consuming by admins

[Isak-Kallini]

Background

Now that we can sell tickets through the webshop, we need a system for consuming tickets. For instance, an event organizer could scan people's tickets on the way into an event. Or if we sell "tickets" for collecting merch (i.e you pay online for some merch and collect it using your ticket) an admin should be able to ensure that you can't use the ticket again.

To-do

Figure out as simple a system as possible and implement it. Create issues for potential future functionality.