AccessControl: Enable RBAC by default (#48813)

* Add RBAC section to settings

* Default to RBAC enabled settings to true

* Update tests to respect RBAC

Co-authored-by: Karl Persson <kalle.persson@grafana.com>

pkg/tests/api/alerting/api_notification_channel_test.go

@@ -775,8 +775,9 @@ func TestNotificationChannels(t *testing.T) {
 
 	{
 		// Create the namespace we'll save our alerts to.
-		_, err := createFolder(t, env.SQLStore, 0, "default")
+		err = createFolder(t, "default", grafanaListedAddr, "grafana", "password")
 		require.NoError(t, err)
+		reloadCachedPermissions(t, grafanaListedAddr, "grafana", "password")
 
 		// Post the alertmanager config.
 		u := fmt.Sprintf("http://grafana:password@%s/api/alertmanager/grafana/config/api/v1/alerts", grafanaListedAddr)