Nav: Split Admin into three sections for new IA (#58229)

* start to split admin into two sections

* most of new admin nav implemented

* landing pages

* hide admin for non-admins

* update admin redirects if not topnav

* clean up

* updated IA for admin (still WIP)

* move plugin pages into correct admin sections

* fix backend unit test

* move correlations into the correct section

* add translations for admin sections

Co-authored-by: Ashley Harrison <ashley.harrison@grafana.com>

pkg/services/navtree/navtreeimpl/admin.go

@@ -166,16 +166,8 @@ func (s *ServiceImpl) getServerAdminNode(c *models.ReqContext) *navtree.NavLink
 		Children:   adminNavLinks,
 	}
 
-	if s.cfg.IsFeatureToggleEnabled(featuremgmt.FlagTopnav) {
-		adminNode.SubTitle = "Manage server-wide settings and access to resources such as organizations, users, and licenses"
-	}
-
 	if len(adminNavLinks) > 0 {
-		if s.cfg.IsFeatureToggleEnabled(featuremgmt.FlagTopnav) {
-			adminNode.Url = s.cfg.AppSubURL + "/admin/server"
-		} else {
-			adminNode.Url = adminNavLinks[0].Url
-		}
+		adminNode.Url = adminNavLinks[0].Url
 	}
 
 	return adminNode