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?
Can you write the inline python in multiple lines?

I also recommend using single quotes for the shell to prevent special symbols from causing unexpected expansions.

This seems to work:

```shell
IP=$(curl -s http://metadata/0.1/meta-data/network | python -c '
import json
import sys
input = json.load(sys.stdin)
print input["networkInterface"][0]["accessConfiguration"][0]["externalIp"]
')
```

It's slightly annoying that the Python script doesn't allow any indentation, but I think it's still fairly readable.