[5282] Added a paragraph about kea-shell / stunnel

doc/guide/agent.xml

@@ -267,6 +267,11 @@ http {
     organization which apply to this setup.</simpara>
   </note>
 
+    <para>When you use a HTTP client without TLS support as <command>
+    kea-shell</command> you can a HTTP/HTTPS translator as stunnel
+    in client mode. A sample configuration is provided in the
+    <filename>doc/examples/https/shell/</filename> directory</para>
+
   </section>
 
   <section id="agent-limitations">