Add client-side settings file #37
Description
Plenty of campuses create forks of codam-web-greeter just to modify some basic things, such as the time window when a computer is reserved for an exam, hiding the calendar in exam mode or removing the exam start countdown.
It would be easier to have a settings file that is accessible by the greeter which modifies how the UI behaves.
This file could also be used for the theming settings, replacing the need for 4 zip files per release and opening up more customization possibilities.