Fix plugin related issues

Fix plugin related issues

- update groovy-maven-plugin (2.0 -> 2.1.1) to fix warning that
  appears in Java 11+. In the future we should switch to the
  gmavenplus plugin
- exclude csar files from being eligible for filtering by the
  maven-resources-plugin in the asdc-controller module.
  This fixes an IndexOutputBounds exception that otherwise occurs
- bind the maven-dependency-plugin:unpack execution to the prepare-package
  phase to only execute it when the Docker images are build

Issue-ID: SO-4201
Change-Id: I339661406a4bce06e59ff5589977688c9d41f459
Signed-off-by: Fiete Ostkamp <Fiete.Ostkamp@telekom.de>