Implement an EventID saved in settings. Currently this is used to scope
clientIDs and entryIDs to an event. The client checks the event currently going on on
the server, and discards its localstorage (containing the clientID) if
it has changed
There are now two dockerfiles. One for production, one for development.
All configuration is now also handled through dotenv files,
which these dotenv files, as well as the included VSCode launch tasks
use.