Arvados

This was envisioned to become a standard way to install Arvados in different environments, but it never got productized beyond our own Jenkins infrastructure. Ansible is a better fit for this: it provides richer, higher-level system configuration tasks; it's easier to write reusable components for different use cases; and it's easier to configure to run in a variety of environments.

Once we stop using it in Jenkins, just remove this command entirely. It can print an informational message pointing people to the Ansible playbooks.