Remove hackathon constants file and replace usage with admin tool

[MaxLeiter]

#527 introduced a front-end interface to set hackathon constants, which means we can remove the hardcoded file and convert all usage to the new system. It's not used very much so should be pretty straight forward

[refcell]

I already built this @MaxLeiter its already in prod :/

[MaxLeiter]

Yeah I think you missed some instances of hackathonConstants usage though? I might’ve been on the wrong branch when I checked. I reference what you built in the description @abigger87