Update supervisord-sample.conf

Bring sample config in line with INSTALL docs
Update supervisord-sample.conf

Fix up the tries argument too
Update INSTALL_Centos.md

Doc updates
Update README.md

Clarify Warning
User Management Updates

- Consolidate the user functions to a singly 'configuration' menu
  item.
- Add a validator for the new user addition step
- Small UI tweaks
Enhance the Worker Debugging Capability