Licensing service (#19903)

* Licensing: supplies a service to handle licensing information

* Licensing: uses the license service further

Uses the license service instead of settings.isEnterprise:
- external team members
- saml
- usage stats

* Licensing: fixes broken tests due to new Licensing service dependency

* Licensing: fixes linting errors

* Licensing: exposes license expiry information to the frontend

pkg/api/index.go

@@ -83,7 +83,7 @@ func (hs *HTTPServer) setIndexViewData(c *m.ReqContext) (*dtos.IndexViewData, er
 		NewGrafanaVersion:       plugins.GrafanaLatestVersion,
 		NewGrafanaVersionExists: plugins.GrafanaHasUpdate,
 		AppName:                 setting.ApplicationName,
-		AppNameBodyClass:        getAppNameBodyClass(setting.ApplicationName),
+		AppNameBodyClass:        getAppNameBodyClass(hs.License.HasValidLicense()),
 	}
 
 	if setting.DisableGravatar {
@@ -372,13 +372,10 @@ func (hs *HTTPServer) NotFoundHandler(c *m.ReqContext) {
 	c.HTML(404, "index", data)
 }
 
-func getAppNameBodyClass(name string) string {
-	switch name {
-	case setting.APP_NAME:
-		return "app-grafana"
-	case setting.APP_NAME_ENTERPRISE:
+func getAppNameBodyClass(validLicense bool) string {
+	if validLicense {
 		return "app-enterprise"
-	default:
-		return ""
 	}
+
+	return "app-grafana"
 }