Move NoAuthenticationProvider under extensions/

New auth providers shouldn't go in guacamole-ext, which is strictly the
API used by extensions to Guacamole. Instead this should be a separate
project like "guacamole-auth-noauth", and should go under extensions/.

extensions/guacamole-auth-noauth/doc/example-configuration-file.xml

@@ -0,0 +1,6 @@
+<configs>
+    <config name="myconfig" protocol="rdp">
+        <param name="hostname" value="rdp-server" />
+        <param name="port" value="3389" />
+    </config>
+</configs>