[Task] Implement prize claim functionality

[JasonBarahan]

Task

Implement the prize claiming functionality. Here's how it should work:

• When a user obtains the minimum number of stamps required to claim the prize, a prompt shows up asking them to claim their prize.
• It is not required to make it a prompt. We can have it be a button that is greyed out until the requirements are met. Once all stamps are collected, the button can be pressed to allow the user to claim their prize.
• Clicking the button prompts them to go to the lounge. Before they claim their prize they are prompted to scan the qr code in the lounge. The person manning the lounge desk can provide this.
• When the QR code is scanned in the lounge, the user is locked out of the stamp rally. (Or we could implement some other behavior when the stamp rally is completed.)

Steps

• Implement the above
• Pass general review