The bouncestorage image hasn't been updated for 4 years and has this
message at the top of the docs:
This repository is outdated; please use dockerswiftaio/docker-swift instead.
However, dockerswiftaio/docker-swift hasn't been updated for 2 years.
Switch to openstackswift/saio instead, which is getting regular updates.
This requires some minor changes to one test, and how we start the
container.
This changes as many of the integraton tests as possible so that they
use port forwarding rather than the docker IP directly.
Using the docker IP directly does not work on macOS and Windows as the
docker images are running in a VM rather than a container.
This adds the PORTS.md document to document which port numbers we are
using for which service as they need to be unique.
