Plugins: Introduce new Flame graph panel (#56376)

* Flamegraph

* Updated flame graph width/height values

* Fix top table rendering issue

* Add feature toggle for flamegraph in explore

* Update tests

* Hide flamegraph from dash panel viz list if feature toggle not enabled

* Show table if no flameGraphFrames

* Add flame graph to testdata ds

* Minor improvement

pkg/plugins/manager/manager_integration_test.go

@@ -164,6 +164,7 @@ func verifyCorePluginCatalogue(t *testing.T, ctx context.Context, ps *store.Serv
 		"candlestick":    {},
 		"news":           {},
 		"nodeGraph":      {},
+		"flamegraph":     {},
 		"traces":         {},
 		"piechart":       {},
 		"stat":           {},

pkg/plugins/pfs/corelist/loadlist_gen.go

@@ -65,6 +65,7 @@ func coreTreeList(lib thema.Library) pfs.TreeList {
 		makeTreeOrPanic("public/app/plugins/panel/bargauge", "bargauge", lib),
 		makeTreeOrPanic("public/app/plugins/panel/dashlist", "dashlist", lib),
 		makeTreeOrPanic("public/app/plugins/panel/debug", "debug", lib),
+		makeTreeOrPanic("public/app/plugins/panel/flamegraph", "flamegraph", lib),
 		makeTreeOrPanic("public/app/plugins/panel/gauge", "gauge", lib),
 		makeTreeOrPanic("public/app/plugins/panel/geomap", "geomap", lib),
 		makeTreeOrPanic("public/app/plugins/panel/gettingstarted", "gettingstarted", lib),