Kube: enable setting the kubeconfig file to use

[nmaguiar]

Is your feature request related to a problem? Please describe.
When using the Kube oPack it can be useful to provide a different kubeconfig file.

Describe the solution you'd like
It should be possible, on a controlled way, to set the Kube config to use a specific kubeconfig file during the object instantiation.

Describe alternatives you've considered
It's possible to set the kubeconfig system property before but this would affect any other concurrent object instantiations:

java.lang.System.setProperty("kubeconfig", "/another/kubeconfig")
var kube = new Kube()

Additional context
n/a