Create Maven archetype for fat jar

[kupferk]

A fat jar might be the easiest way for certain cloud deployments (databricks, SageMaker, ...). The fat jar should be created via Maven, so it might be a good idea either to extend the current archetype or to create a new one.

Of course there are things that we need to take care of:

• loading default-namtspace.yml from classpath
• loading project from classpath
• loading plugins from classpath
• loading logging config from classpath

We could think about loading the project from a accessible location like S3