Add example of how to integrate haproxy

[kashalls]

This is how I chose to implement haproxy in my scenario.
I use it to load-balance a single master (really amazing right?) on my home cluster network.

My haproxy.cfg is what I use in production and can be used as an example.

I

[Ulrar]

I just used this to set it up myself, works great, thanks !
One note is that it looks like port 80 and 443 are already used, so I had to start haproxy on two other ports and use port forwarding (to one of the UDM's internal IPs, not localhost) to get it working.
Also open these ports in the firewall

btw it looks like you still have a couple of references to pihole in and dns in the readme and startup scripts.