AKPlan: Hide night hours
Using the Fullcalendar property slotMinTime: "06:00:00", slotMaxTime: "24:00:00",
, we could hide the night hours.
The min value should be determined dynamically, starting with the earliest hour of all AKs not started yet.
It probably makes sense to completely hide all AKs that ended, e.g., two hours ago on the wall, therefore even with AKs starting in the middle of the night, the night hours will only be visible as long as needed. The max value will make sure that there is an indicator showing that an AK will go beyond midnight if needed.