Add note in FAQ about way to have different amount of spaces at a location

[smessie]

When a reservation slot is made for a room with 32 spots all is good. But once we realise, hey theres this possibility to fit much more people than we realised or corona is done and might be able to stack students more efficiently then we might want to change the room size to 60 spots. But all the previous timeslots will already have the 32 hard coded. Instead of keeping track of the amount of spots in the timeslots we might want to reference to the location who knows how much spots there are.

We don't do this on purpose: doing it this way allows you to schedule in the change in advance. if you know that there will be more spaces next week, you can keep the smaller spaces this week while already having the larger spaces next week. If we track the location size this becomes impossible, and it also might make overreservations possible: if it's full and you make it smaller.

Action: add this to the Manager page in the user manual / FAQ.