RAD-289 Cannot discontinue order
Discontinuation of order fails via order form if accessing the page via UUID.
Somehow spring sets the orderId of the discontinuationOrder modelAttribute to this UUID
which causes a type cast error probably rooting in the PropertyEditor of the order. Therefore
BindingResults hasErrors.
* add DiscontinuationOrderRequest to encapsulate discontinuation orderer and
reason
* revamp old validator to DiscontinuationOrderRequestValidator
* use validator in RadiologyOrderFormController via @Valid annotation
* add test for postDiscontinueRadiologyOrder if discontinuation request was not
valid
