Drop the Terraform configurations; cloud-init is the deployment path

Drop the Terraform configurations; cloud-init is the deployment path

A Vole instance is one package, one configuration file, and one directory.
The first-boot file that installs the package and writes the configuration
is that same work described once, and it needs no provider, no state file,
and no cloud token with write access to an account. What Terraform did
outside the machine — firewall, address, DNS record — is three fields in a
console the operator already has open.

So the three configurations go, and with them what existed only to check
them: the pinned Terraform download in the verify image, the `fmt -check`
step, the .terraform entries in the ignore file, and the directory skip in
the link checker. The deployment check now needs python3 and PyYAML and
nothing else — no network, no credentials.

deploy/README.md keeps the reasoning, so the next person tempted to add a
provider back sees what it would buy and what it would cost.

The templates' header comments no longer name a renderer that is gone:
render.sh fills them in, and check-deploy.py renders them the same way.