Provide a simple way to start and stop ephemeral docker containers that
host CloudDB. The runner enables multiple instances to run concurrently
and to have them exposed on ephemeral ports on the host when running
unit tests outside of a container.

Change-Id: I07f206db032d0cdbfca4f4b5fc0dd473058a67fc
Signed-off-by: Matthew Sykes <sykesmat@us.ibm.com>