wip: k8s tutorial changes

[sbenderli]

@elixir-1 Here is my WIP changes for the k8s tutorial. There's a corresponding set of tutorial docs in the star repo in the branch docs-k8s-etcd

A few callouts:

1. Where possible, I tried to simplify the directory and file structure. This should also help with the flow of the tutorial and reduce some unnecessary steps and text.
2. The health-checker actually checks for the health of the cluster. This is required in kubernetes where there isn't a "dependsOn" type feature. I do like this better though, since it shows customers a more real case of how to emit their setup complete signal.
3. I did not include the etcd helm chart folder, but I could since it is part of the "working directory" as you go through the tutorial, which seems to be what we're going for with this project.