Alerting: Improve integration with dashboards (#80201)

* Add filtering by dashboard UID annotation

* Update the inline doc for search

* Add AlertRulesDrawer to the dashboards toolbar

* Use DashboardPicker as a filter on the alert rules page

* Fix accessibility errors

* Update drawer subtitle

* Display Alerting toolbar button only if there are linked alert rules

* Change toolbar rendering method, prevent displaying when no linked rules

* Improve text

* Use React.lazy to load the Alert rule toolbar button and drawer when needed

public/app/app.ts

@@ -71,6 +71,7 @@ import { GrafanaJavascriptAgentBackend } from './core/services/echo/backends/gra
 import { KeybindingSrv } from './core/services/keybindingSrv';
 import { startMeasure, stopMeasure } from './core/utils/metrics';
 import { initDevFeatures } from './dev';
+import { initAlerting } from './features/alerting/unified/initAlerting';
 import { initAuthConfig } from './features/auth-config';
 import { getTimeSrv } from './features/dashboard/services/TimeSrv';
 import { EmbeddedDashboardLazy } from './features/dashboard-scene/embedding/EmbeddedDashboardLazy';
@@ -153,6 +154,8 @@ export class GrafanaApp {
       configureStore();
       initExtensions();
 
+      initAlerting();
+
       standardEditorsRegistry.setInit(getAllOptionEditors);
       standardFieldConfigEditorRegistry.setInit(getAllStandardFieldConfigs);
       standardTransformersRegistry.setInit(getStandardTransformers);