Fully qualify all paths on the webserver

In order to support Knox proxying of the debug webui, we should fully qualify all links on our debug web ui with the host:port.

This will allow us to create rewrite rules that do the transform:
<a href="host:port/path">...</a>
=>
<a href="<knox-host>/topology/impalaui/path?host=host&port=port>...</a>

One complication is preventing regressions when future links are added, since this is a difficult thing to test for