Change API for PdmObjectHandle and PdmFieldHandle

* Refactor interface to PdmObjectHandle and PdmFieldHandle
Return objects instead of passing in structures as parameters

* Add nodiscard to several functions
* Remove redundant this->
* Rename to ptrReferencedObjectsByType

ApplicationLibCode/ProjectDataModel/RimContourMapProjection.cpp

@@ -1720,8 +1720,7 @@ void RimContourMapProjection::fieldChangedByUi( const caf::PdmFieldHandle* chang
 
     baseView()->updateConnectedEditors();
 
-    RimProject* proj;
-    firstAncestorOrThisOfTypeAsserted( proj );
+    RimProject* proj = RimProject::current();
     proj->scheduleCreateDisplayModelAndRedrawAllViews();
 }