[testing] Use image configuration to store and define image data

[duncdrum]

For the images used in the integration test phase, there is no reason to pass al information about images to maven manually, thats what the image coniguration of the plugin is for, let's use it more efficiently.

define images inside the pom, so we don't have to provide repo.name + repo.port + image.name. Together with #30 the only thing that should be available to pass via mvn … is image.tag and image.alias

mvn -B -q -Ddocker.image.alias=Fusion -Ddocker.image.tag=nightly verify

Should run IT on a single image, by default

mvn -B -q verify

should run the IT test on all images defined in the pom in parallel, with randomly assigned external ports.