Slightly better integration test docs

[Tom Zeller]

> Mostly Rod,

As a related follow up, it turns out that my use of the
maven-dependency-plugin in the integration tests project is not
actually supported by m2e (the Maven plugin for Eclipse), so if we are
looking for alternatives to Maven to unpack and copy files to the IdP
and Jetty distributions, that's a reason to do so. Copying and
unpacking dependencies before executing the package phase is not
supported by m2e, AFAICT.