include links to haproxy base container

[drjasonharrison-vp-eio]

It would be helpful to include links to the haproxy base containers.
balenaOS puts the root haproxy configuration files in different locations than some may expect.

[imrehg]

That's sensible to have more documentation, @drjasonharrison-vp-eio
In some ways that part is also showing different ways of creating projects (per-architecture / per-device-type Dockerfile). Maybe that's less important, and should just build Haproxy from source? (though the time it takes is a downside for a getting started project, most likely).

Where would people expect the haproxy configuration to be put? Maybe we'll have to adjust the demo project to be more conforming to the best practices of haproxy projects, and any info is appreciated.