K8s action support

This commit enables k8s actions by executing them the
same way as any other ns-action. It needs a mandatory
parameter which is application-name.

This commit depends on another commit in LCM.
https://osm.etsi.org/gerrit/#/c/osm/LCM/+/8767/



Change-Id: I375fb93d55f1255d425f229fe1a88968b19ae3d0
Signed-off-by: Dominik Fleischmann <dominik.fleischmann@canonical.com>