DashboardScene: First step to loading the current dashboard model and rendering it as a scene (#57012)

* Initial dashboard loading start

* loading dashboard works and shows something

* loading dashboard works and shows something

* Minor tweaks

* Add starred dashboards to scene list page

* Use new SceneGridLayout

* Allow switching directly from dashboard to a scene

* Migrate basic dashboard rows to scene based dashboard

* Review nit

Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>

public/app/features/dashboard/components/DashNav/DashNav.tsx

@@ -338,6 +338,16 @@ export const DashNav = React.memo<Props>((props) => {
 
     buttons.push(renderTimeControls());
     buttons.push(tvButton);
+
+    if (config.featureToggles.scenes) {
+      buttons.push(
+        <ToolbarButton
+          tooltip={'View as Scene'}
+          icon="apps"
+          onClick={() => locationService.push(`/scenes/dashboard/${dashboard.uid}`)}
+        />
+      );
+    }
     return buttons;
   };