[RichString] Add markdown support
Supporting markdown requires the 'Markdown' python packages, and since it
widely available on the target platforms adding it as a strong requirements
will not be a big constraint.
Closes #3814302
<html>
<head>
<!-- dependencies -->
<script type="text/javascript">
var JSON_BASE_URL = '';
</script>
<script type="text/javascript" src="../../data/jquery.js"></script>
<script src="../../data/cubicweb.js" type="text/javascript"></script>
<script src="../../data/cubicweb.htmlhelpers.js" type="text/javascript"></script>
<script src="../../data/cubicweb.python.js" type="text/javascript"></script>
<script src="../../data/cubicweb.compat.js" type="text/javascript"></script>
<script src="../../data/cubicweb.ajax.js" type="text/javascript"></script>
<!-- qunit files -->
<script type="text/javascript" src="../../../devtools/data/qunit.js"></script>
<link rel="stylesheet" type="text/css" media="all" href="../../../devtools/data/qunit.css" />
<!-- test suite -->
<script src="cwmock.js" type="text/javascript"></script>
<script src="test_ajax.js" type="text/javascript"></script>
</head>
<body>
<div id="main"> </div>
<h1 id="qunit-header">cubicweb.ajax.js functions tests</h1>
<h2 id="qunit-banner"></h2>
<ol id="qunit-tests">
</body>
</html>