RicImportGridAndSummaryEnsembleFeature: Add feature for importing grid and summary ensembles

- Add RicImportGridAndSummaryEnsembleFeature with icon and menu/toolbar registration
- Register in main window toolbar, import menu (both windows)
- Add feature to plot window Standard toolbar
- Wire up post-import view and plot creation
- Skip grid/summary ensemble creation when no files of that type are found
- Keep focus in plot window when no grid ensembles are created

ApplicationLibCode/ProjectDataModel/RimReservoirGridEnsemble.h

@@ -106,6 +106,7 @@ public:
     RimEclipseView*              addViewForCase( RimEclipseCase* eclipseCase );
     std::vector<RimEclipseView*> allViews() const;
     std::set<RimEclipseCase*>    casesInViews() const override;
+    RimEclipseViewCollection*    viewCollection() const;
 
     // Well target mapping
     void                               addWellTargetMapping( RimWellTargetMapping* wellTargetMapping );