Reconsider treatment of "!exists?" in KubernetesResource classes

[KnVerey]

Currently, this status is set if we get any kind of error from the API server (404 or otherwise) and is assumed to be transient. A more sensible approach might be to explicitly set @exists = false on a 404 and consider the resource to have failed immediately when we see that. If the API server has no record of it after the creation request, it isn't going to spontaneously appear. If that happens because the user deleted the resource immediately out of band, optimistically polling until the timeout seems like the wrong behaviour.