XML for mod_proxy.

Note: This one was and still is is pretty rough shape, both in terms of

1. Stinky markup (why use a <p> when a couple <br>s will do?)

2. Out of date and insufficient content.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93820 13f79535-47bb-0310-9956-ffa450edef68