Enable restoring the default names of project configuration items

* Enable support for this in all ProjectConfiguration items
   (Targets, projects, BCs, DCs, RCs, etc.). This is nicer
   than having custom code in individual configuraiton items.

Reviewed-by: dt

src/plugins/cmakeprojectmanager/cmakerunconfiguration.h

@@ -97,6 +97,7 @@ private slots:
 protected:
     CMakeRunConfiguration(CMakeTarget *parent, CMakeRunConfiguration *source);
     virtual bool fromMap(const QVariantMap &map);
+    QString defaultDisplayName() const;
 
 private:
     void ctor();