(#386) Added "Delete" to the grid case group context menu

Note: Used to be "Close" in the old tree view. Using existing feature
for deletion, for now.

ApplicationCode/ProjectDataModel/RimProject.cpp

@@ -626,7 +626,7 @@ void RimProject::actionsBasedOnSelection(QMenu& contextMenu)
         {
             commandIds << "RicEclipseCaseNewGroupFeature";
             commandIds << "RicPasteEclipseCasesFeature";
-            //commandIds << "RicEcliseCaseGroupCloseFeature";
+            commandIds << "RicDeleteItemFeature";
         }
 
         else if (dynamic_cast<RimCaseCollection*>(uiItem))