Make sure serviceType, shipmentTerm and serviceContract are the same for different Bookings on the same SI

[HenrikHL]

In order to get a serviceType, shipmentTerm or serviceContract for a TransportDocument (TD) it is necessary to get this information from the Booking. Since the BookingReference is conditional in the ShippingInstruction (SI) "header" it might be necessary to go to CargoItems in order to get a BookingReference.
There is no order on CargoItems so no matter which Booking you get from a CargoItem - the above 3 values (5 since there is both an origin and a destination) need to be the same.
Solution: When POSTing or PUTting a SI - serviceType, shipmentTerm and serviceContract needs to be checked in all linked BookingReferences and make sure they are the same - if not - the POST or PUT needs to be rejected.