Comprehensive Change of ExternalData in Kitchen Order

In Api V9Preview1, two new operations were added - ComplexAddOrUpdateKitchenOrderAndItemsExternalData and ComplexDeleteKitchenOrderAndItemsExternalData.

ComplexAddOrUpdateKitchenOrderAndItemsExternalData - allows for bulk adding/updating of ExternalData for a kitchen order and all its items.

ComplexDeleteKitchenOrderAndItemsExternalData - allows for the simultaneous deletion of all unnecessary ExternalData for a kitchen order and all its items.

These operations will be especially useful in cases of active use of external data: the operations generate the notification KitchenOrderChanged only once, and they are executed faster than multiple uses of AddOrUpdateKitchenOrderExternalData / AddOrUpdateKitchenOrderItemExternalData / DeleteKitchenOrderExternalData / DeleteKitchenOrderItemExternalData.