Add option to replace SSH keys with short-lived certificates by applying Cloudflare SSH with Access for Infrastructure

[RicoSchmitt]

Cloudflare Access allows securing SSH (and other protocols) by issuing ephemeral client certificates through WARP. With this setup, servers no longer need to expose port 22 publicly, since all connections are proxied through Cloudflare.
This removes the burden of generating and distributing static SSH key pairs. Instead, authentication and authorization are handled by Cloudflare Access policies, which can be managed centrally from the dashboard or defined declaratively via Terraform. Please find these docs for further reference.

I have already implemented this for some clusters, but the process is currently manual. I would be interested in contributing a script to automate the setup of SSH Access for Infrastructure if the community considers it in scope. Looking forward to your thoughts on this!