Instructions on how to create Ubuntu workers should be documented

[geremyCohen]

In 01-path-basics/102-your-first-cluster/readme.adoc we bring up Amazon Linux-based workers. Many people may be interested in also learning how to bring up Ubuntu-based workers.

https://cloud-images.ubuntu.com/aws-eks/ should be referenced to demonstrate how to bring in Ubuntu nodes via the official Canonical CF template + image.

[buzzsurfr]

The goal of the workshop is to start the user on kubernetes. I would prefer to stick to a single worker OS, but I could see this as an appendix item.