Containerize HAProxy for HA

Containerize HAProxy for HA

This service allows configuring and deploying HAProxy containers
in a HA overcloud managed by pacemaker.

The containers are managed and run by pacemaker. Pacemaker runs the
standard Kolla image but overrides the initial command so that
it explicitely calls HAProxy. This way, we shield ourselves from any
unexpected future change in Kolla.
This container needs to use the 'docker_config' section to invoke
puppet (as opposed to 'docker_puppet_tasks'), because due to the HA
composability each resource creation needs to happen on the bootstrap
node of that service and 'docker_puppet_tasks' will only run on the
controller/primary role.

Co-Authored-By: Michele Baldessari <michele@acksyn.org>
Closes-Bug: #1692908

Depends-On: Ifcf890a88ef003d3ab754cb677cbf34ba8db9312

Change-Id: I2f679bfe195733f4507e9b9e920b678e1370bb82