Enhance the CAS client and what it displays

[mapgrady]

First, In dockerized-idp-testbed/php-cas/var-www-html/php-cas/index.php, I'd recommend commenting out the line:

phpCAS::setExtraCurlOption( CURLOPT_SSLVERSION, 6 );

so that the default behavior of negotiating protocol happens. And then later, where it displays Success, add the following that would print out all the attributes received from the IdP:

<h1>Successful Authentication!</h1>

<p>the user's login is <b><?php echo phpCAS::getUser(); ?></b>.</p>
<p>phpCAS version is <b><?php echo phpCAS::getVersion(); ?></b>.</p>
<p><a href="/">Main Menu</a></p>
<h3>User Attributes</h3>
 <ul>
<?php
foreach (phpCAS::getAttributes() as $key => $value) {
    if (is_array($value)) {
        echo '<li>', $key, ':<ol>';
        foreach ($value as $item) {
            echo '<li><strong>', $item, '</strong></li>';
        }
        echo '</ol></li>';
    } else {
        echo '<li>', $key, ': <strong>', $value, '</strong></li>' . PHP_EOL;
    }
}
    ?>
</ul>
  </body>
</html>