mod_spam_reporting: Add support for XEP-0377 0.3
Support 'urn:xmpp:reporting:1', see
https://xmpp.org/extensions/xep-0377.html#revision-history-v0.3
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Registration succeeded!</title>
</head>
<body>
<h1>Registration succeeded!</h1>
<p>Your account is</p>
<pre>{jid}</pre>
<p>- happy chatting!</p>
</body>
</html>