Better output when incorrect args in uninstall

[alenkacz]

What this PR does / why we need it:
This is the new output. I think that is much more user friendly.

./bin/kubectl-kudo uninstall mysql-instance
Error: The command expects no arguments and --instance flag must be provided.
 Usage:
  kubectl-kudo uninstall [flags]

Examples:
kubectl kudo uninstall --instance flink

Flags:
  -h, --help              help for uninstall
      --instance string   The instance name.

Global Flags:
      --home string           location of your KUDO config. (default "/Users/alenavarkockova/.kudo")
      --kubeconfig string     Path to your Kubernetes configuration file. (default "/Users/alenavarkockova/.kube/config")
  -n, --namespace string      Target namespace for the object. (default "default")
      --request-timeout int   Request timeout value, in seconds.  Defaults to 0 (unlimited)
  -v, --v                     log level for V logs

Partial improvement for #1055

[gerred]

nice 🎉