mod_external_services: Factor out public function for converting to XML Along with the previous commit, allows building the XML thing yourself, should you wish to send it yourself or use it in a different context than an iq reply. API change: The 'reply' is removed from the event.

<tr>
  <td colspan="2">
    <script src="https://hcaptcha.com/1/api.js" async defer></script>
    <div class="h-captcha" data-sitekey="{captcha_public_key}"></div>
  </td>
</tr>