Add Helpdesk message rate limit

Add this code to site.php file:

//Lock user if he submit more than 10 message within 1 day
Am_Di::getInstance()->hook->add('helpdeskMessageAfterInsert', function(Am_Event $e) {
    /** @var HelpdeskMessage $msg */
    $msg = $e->getMessage();

    $user = $msg->getTicket()->getUser();

    $cnt = $e->getDi()->db->selectCell(<<<CUT
        SELECT COUNT(*) FROM ?_helpdesk_message m
            LEFT JOIN ?_helpdesk_ticket t USING (ticket_id)
            WHERE m.admin_id IS NULL
                AND t.user_id=?
                AND dattm > ?
    CUT, $user->pk(), sqlTime('-1day'));

    if ($cnt > 10) {
        $user->lock(true);
    }
});