Repository transfer has to be confirmed, if user can not create repo for new owner (#14792)

* make repo as "pending transfer" if on transfer start doer has no right to create repo in new destination

* if new pending transfer ocured, create UI & Mail notifications

modules/convert/notification.go

@@ -52,8 +52,14 @@ func ToNotificationThread(n *models.Notification) *api.NotificationThread {
 		result.Subject = &api.NotificationSubject{
 			Type:  "Commit",
 			Title: n.CommitID,
+			URL:   n.Repository.HTMLURL() + "/commit/" + n.CommitID,
+		}
+	case models.NotificationSourceRepository:
+		result.Subject = &api.NotificationSubject{
+			Type:  "Repository",
+			Title: n.Repository.FullName(),
+			URL:   n.Repository.Link(),
 		}
-		//unused until now
 	}
 
 	return result