Work Items for Kubernetes Reliability

This PR proposes a shared Google document for discussing work items for how we can improve Kubernetes reliability: [Kuberenetes Reliability](https://docs.google.com/document/d/1wwh569PwAWvEZcLc0gHSrO1xr-N-T5cnKjepjc0dXvI/edit#)

Please consider identifying pain points and work items to help us improve the reliability of Kubernetes. Please can you initially consider adding material to the Google doc which is currently editable by anyone. Then (quite soon-ish) we can transplant the gist of the document into work items spelled out in the README.md file in the PR.