Allow server to start on random available ports

[rslemos]

It would be nice to allow the server to start on random available ports.

That is relevant in the context of a continuous integration server, because many projects might be using arquillian for integration testing, and many jobs could happen to be running in parallel.

It would be sad if one job failed because "address is alreay in use".
Or even worse: project A exercise its endpoints onto a server brought up by another branch of same project A (and another CI job).

Besides starting on random port, that chosen port must be captured by @ArquillianResource private URI serverURI.