Function churchresource_getEventChangeImpact

Get booking changes 1. Check from originEvent if this is in newEvent 2a. If not in newEvent, if it is in pastEvent, everything fine. Nothing changed 2b. If is not in newEvent and in pastEvent, then it was deleted! 3. If is in newEvent, then diff the changes 4. Check if newEvent is not in originEvent, then there is something new