Add a script for generating CA signed certs, and a client cert.

@filbranden @jbeda Take a look.  @derekwaynecarr is there an easy way to get the IP address on a vagrant cluster?
We should use the v1 metadata API.  Again, we don't need to parse out the network stuff but instead can get the externalIP directly:

```
curl -s -H Metadata-Flavor:Google http://metadata.google.internal./computeMetadata/v1/instance/network-interfaces/0/access-configs/0/external-ip
```