Functional tests

This is a derivation of the † functional tests that use the `maven-invoker-plugin`, but is configured in a way that is IDE-friendly.
Ok - I see it now - but you're overloading existing pom properties with this, which is something I've traditionally seen avoided - and I think it works precisely because you are setting these properties to the same values that would already be set in the functional-tests/pom.xml because you set <parent> such that ${project.value} and ${project.groupId} area already inherited values from the parent pom. 

In other words, the filtering going on here is having no different effect than you would already naturally get form the inheritance.