Self service code setup for flag builders

[gangrif]

Currently, code generation and sync with flag builders is manual. The scoreboard administrator has to generate random codes, and make sure they are unique, and handed out to the flag builders.

Currently, codes are by default single-use. Which means the random part of the code needs to be unique, and cant be handed out to more than one flag builder. This is manageable at a small scale, but if you're doing a larger scale ctf this will quickly become difficult to manage, and error-prone.

I can imagine two ways to deal with this.

1. We ditch the single-use code mechanism. I don't love this idea, but its an option.
2. Create a self-service portal, where flag builders can login and generate codes, and then give them a sqlite database containing their codes and flag id's.