Unify Quickstart examples

[galpha]

Currently gradoop contains multiple quick start examples. One within gradoop-examples module with a fitting wiki description and one within gradoop-quickstart (archetype). We should only maintain one example, preferably within the new quickstart module.

[p-f]

The quickstart example does not contain an example anymore, just a class with a prepared GradoopFlinkConfig. I think we should just add a wiki entry describing how to use the archetype, after the release as a stable version