Signed-off-by: Guy Margalit <guymguym@gmail.com>
Co-Authored-By: Sébastien Han <seb@redhat.com>
Co-Authored-By: Travis Nielsen <tnielsen@redhat.com>

This change is meant to allow running operators locally on a developer machine.
The idea is to allow faster development cycles by reducing the time and complexity of building -> deploying -> debugging on cluster.

For operators that rely only on kubernetes API this works easily - see cockroachdb and minio examples in development-flow doc.

The change includes:

- rook.NewContext() - Refactored to remove repeating initialization code that was copy-pasted in most of the operators in order to create the clusterd.Context and the Clientsets. Also it detects the mode of working in-cluster vs external and sets up the external mode with standard user config (~/.kube/config) and a job executor.
- rook.GetOperatorImage() - Refactor this repeating code in many operators to detect the operator pod image. Also added ...