Alerting: Next gen Alerting page (#28397)

* create page and sidebar entry

* add components for query editor and definition

* split pane things

* add reducer and action

* implement split pane and update ui actions

* making things pretty

* Unify toolbar

* minor tweak to title prefix and some padding

* can create definitions

* fix default state

* add notificaion channel

* add wrappers to get correct spacing between panes

* include or exclude description

* implement query editor

* start on query result component

* update from master

* some cleanup and remove expressions touch ups

Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

public/app/routes/routes.ts

@@ -28,7 +28,7 @@ export function setupAngularRoutes($routeProvider: route.IRouteProvider, $locati
     .when('/', {
       template: '<react-container />',
       //@ts-ignore
-      pageClass: 'page-dashboard',
+      pageClass: 'page-explore',
       routeInfo: DashboardRouteInfo.Home,
       reloadOnSearch: false,
       resolve: {
@@ -556,6 +556,17 @@ export function setupAngularRoutes($routeProvider: route.IRouteProvider, $locati
           ),
       },
     })
+    .when('/ngalerting', {
+      template: '<react-container />',
+      resolve: {
+        component: () =>
+          SafeDynamicImport(
+            import(/* webpackChunkName: "NgAlertingPage"*/ 'app/features/alerting/NextGenAlertingPage')
+          ),
+      },
+      //@ts-ignore
+      pageClass: 'page-alerting',
+    })
     .otherwise({
       template: '<react-container />',
       resolve: {