Generate HAproxy iptables rules for containerized HA deployments

Generate HAproxy iptables rules for containerized HA deployments

The containerized HAproxy service can only specify steps to be run in
containers, i.e. it cannot runs the regular puppet steps on bare metal
at the same time. A side effect is that the dedicated HAproxy iptables
rules are no longer generated.

Update the docker_config step to fix the creation of iptables rules
for HAproxy and persist them on-disk as before.

Co-Authored-By: Michele Baldessari <michele@acksyn.org>
Closes-Bug: 1697387

Change-Id: Ib5a083ba3299a82645f1a0f9da0d482c6b89ee23