CDK-281. Push Kite artifacts to maven central

Note that this has some POM information duplicated between kite-app-parent/cdh4/pom.xml and the top-level POM - this is to avoid having to make the application POM extend the Kite top-level POM, which has lots of things in it that users won't need. And Maven Central requires certain POM elements which is why I put them in the app POM.