Add waiting list

For people who didn't get anything are put on a waiting list in order. So that we can open the booking again and "reprocess the waitlist" if the campaign is reopened and there are more things. Maybe it's not even a waiting list, but just a way of reprocessing bookings that wasn't confirmed. So when they open a booking again they should get a popup "do you wanna reprocess the comments?" And then it reprocesses the "Not approved" and "Partially approved" ones in order of the timestamp