Port forwarding in Sonolark

[johnSchnake]

When trying to see if a service/pod is working correctly it can be very useful to use port forwarding. This should be available via sonolark in some capacity.

I'm not sure the user interface that would be ideal, but kubernetes/client-go#51 gives an example how to do it and links to another article about it: https://gianarb.it/blog/programmatically-kube-port-forward-in-go

In my current use case I just need to do the port forward, check if it works and I can access it or not. There may be cases where you wanted it longer living though so something may need to be done like:

claim = kube.portforward(...)
...
kube.endportforward(claim)

And obviously this needs to be non-blocking in the code.