Navigation: Implement logic for docking nav menu (#76188)

* Create a state for dockedMegaMenu and the function to manage it

* Add the dockedMenu icon and handle the status when clicking it

* Add Megamenu to section nav area when it is docked

* get logic working

* fix mobile

* refactor state + persist in localStorage

* adjust icon and don't use position absolute

* restore old rudderstack tracking

* use Flex instead

* adjust feature toggle to be experimental

* extract out localStorage handling into utils

* don't need separate file

* use store.set/get instead

---------

Co-authored-by: eledobleefe <laura.fernandez@grafana.com>

pkg/services/featuremgmt/registry.go

@@ -164,7 +164,7 @@ var (
 		{
 			Name:         "dockedMegaMenu",
 			Description:  "Enable support for a persistent (docked) navigation menu",
-			Stage:        FeatureStagePublicPreview,
+			Stage:        FeatureStageExperimental,
 			FrontendOnly: true,
 			Owner:        grafanaFrontendPlatformSquad,
 		},

pkg/services/featuremgmt/toggles_gen.csv

@@ -22,7 +22,7 @@ disableSecretsCompatibility,experimental,@grafana/hosted-grafana-team,false,fals
 logRequestsInstrumentedAsUnknown,experimental,@grafana/hosted-grafana-team,false,false,false,false
 dataConnectionsConsole,GA,@grafana/plugins-platform-backend,false,false,false,false
 topnav,deprecated,@grafana/grafana-frontend-platform,false,false,false,false
-dockedMegaMenu,preview,@grafana/grafana-frontend-platform,false,false,false,true
+dockedMegaMenu,experimental,@grafana/grafana-frontend-platform,false,false,false,true
 grpcServer,preview,@grafana/grafana-app-platform-squad,false,false,false,false
 entityStore,experimental,@grafana/grafana-app-platform-squad,true,false,false,false
 cloudWatchCrossAccountQuerying,GA,@grafana/aws-datasources,false,false,false,false