Allow a schedule to become a normal schedule on a certain date
Summary
As discussed in and after our meeting with shopMason, we currently have two types of schedules, normal and special. Special schedules are designed to be temporary, while normal schedules are designed to be a bit more permanent. There is, however, not yet a way to let a new normal schedule take over an existing one on a schedule. One could work around this by making that new schedule a special schedule, but then you're left without a special schedule slot at all.
We should allow admins to assign a schedule, maybe a special schedule with an extra time parameter, to a facility in advance to, in the future, become a normal schedule. This would be very useful going forward as groups like shopMason obtain hours weeks or even months in advance.