configure kubectl autocomplete and alias k in jumpbox vm

Improve the automation that creates the jumpbox vm to 

1. alias k to kubectl
2. add bash completion 

```bash
echo 'source <(kubectl completion bash)' >>~/.bashrc
echo 'alias k=kubectl' >>~/.bashrc
echo 'complete -o default -F __start_kubectl k' >>~/.bashrc
```

see https://kubernetes.io/docs/tasks/tools/install-kubectl-linux/#enable-kubectl-autocompletion
