Access.md added.
Minor changes and fixes.
Redefine Actors; use consistently; Capitalize k8s.
Defer details of Authorization to a separate doc.
Separate userAccount and auth-method.  Add UID.
More Goals and less impl details of Authn.
Expanded discussion of projects in the REST API based on feedback.
Rename project to namespace and reference #1114.
Removed file not ready to share.
Merge pull request #891 from erictune/security_md

Access.md added.