[forge] notify admins on new user creation

Signed-off-by: Ryan Lerch <rlerch@redhat.com>

roles/openshift-apps/forgejo/templates/values.yaml.j2

@@ -621,6 +621,7 @@ gitea:
       USER_DISABLED_FEATURES: "deletion"
       EXTERNAL_USER_DISABLE_FEATURES: "deletion"
       DEFAULT_EMAIL_NOTIFICATIONS: "enabled"
+      SEND_NOTIFICATION_EMAIL_ON_NEW_USER: true
 
     ## @param gitea.config.security Site security settings
     security: {}