Add a status command

[dlorenc]

This should determine whether or not the cluster is running correctly.

[vishh]

Why is this necessary?

[dlorenc]

It's necessary at least for integration testing and possibly as a diagnostic for users. Eventually I'd like to have a test suite that actually calls things like:

minikube start
assert minikube status == Running
minikube stop
assert minikube status == Stopped
minikube delete
assert minikube status == Does Not Exist

etc.

If users get into trouble we can also ask them to attach the output of this command, which might help diagnose issues.

[vishh]

SGTM

[dlorenc]

Closed by #27