K8s autodiscovery (#453)
* Add a new dependency on Kubernetes package
* Add and store a new flag about automatic nodes discovery from a pod
* Implement the listing of nodes
* Add tests to cover the k8s node listing
* Fix the k8s listing test to ensure the load incluster function is actually called
* Add more help to the k8s node discovery flags, and cross-reference them.
* Add a note on the Kubernetes auto-discovery in the main README file
* Move the kubernetes discovery from conf to modules/discovery
* When running with --pods, run the Kubernetes auto discovery
* Also mention that the auto discovery is always on when using --pod
Co-authored-by: Mikolaj Pawlikowski <[email protected]>
