CDK-643: Initial draft of how to use maven with Kite

* Mostly this just documents the warning about how configuration files
  can be pulled into the build.
This doesn't affect the maven plugin, it's used by the examples so you can run the examples on a physical cluster. After I wrote this, I immediately that that we probably should have done this in an examples parent POM rather than the general app parent.

Given that we're so close to a release, what do we want to do? I'm OK with breaking running the examples on a real cluster as we've never had good support for that. That would have use remove the profiles that support this from the app parent and open an issue to create an examples parent pom or put the profiles into each example.

Alternatively, I could have the profiles require explicit enabling. That means you'd have to both set the environment variable and pass an option to maven on the command-line.

Thoughts?