Fix from header and set email address to admin list

Fixes #168 (emails "from GOCDB" should come from [email protected]).

lib/Gocdb_Services/NotificationService.php

@@ -172,7 +172,7 @@ private function send_email($role_requested, $requesting_user, $entity_name, $ap
         );
 
         $email = $approving_user->getEmail();
-        $headers = "From: no-reply@goc.egi.eu";
+        $headers = "From: GOCDB <gocdb-admins@mailman.egi.eu>";
 
         if (get_config_send_email()) {
             mail($email, $subject, $body, $headers);