Turn a fresh machine into an instance on first boot

Turn a fresh machine into an instance on first boot

A new instance is one package, one configuration, one directory, and one
account. Assembling that by hand is where a first deployment goes wrong:
the capability the hardened unit needs for ports 80 and 443, the order that
makes the package's own init harmless, and the fact that the first instance
admin has to be granted on the host.

deploy/cloud-init/vole.yaml is that assembly. It stages two configurations,
one that lets Vole hold its own certificate and one that leaves TLS to a
proxy, then installs the package, writes the configuration, creates the
instance admin, and starts the service. Running it again changes nothing.

render.sh renders it for providers that take user data without Terraform,
using the placeholder list as the contract with the template.

The three Terraform configurations create the machine, its firewall, its
address, and optionally the DNS record, and hand it that same file. They are
root modules: init and apply, three variables, no other file to edit.

First boot is not configuration management. apply does not upgrade an
instance or touch its data, because users.db migrates in place and cannot be
rolled back.