Auth: Add empty role definition (#64694)

* Allow setting role as None

Co-authored-by: gamab <gabi.mabs@gmail.com>

Seeking for places where role.None would be used

Co-authored-by: Jguer <joao.guerreiro@grafana.com>

Adding None role to the frontend

Co-authored-by: Jguer <joao.guerreiro@grafana.com>

unify org role declaration and remove from add permission

fix backend test

fix backend lint

* remove role none from frontend

* Simplify checks

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

* nits

---------

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

pkg/middleware/auth.go

@@ -20,8 +20,8 @@ import (
 
 type AuthOptions struct {
 	ReqGrafanaAdmin bool
-	ReqSignedIn     bool
 	ReqNoAnonynmous bool
+	ReqSignedIn     bool
 }
 
 func accessForbidden(c *contextmodel.ReqContext) {