Replace varnish with Caddy's cache directive

[FireMasterK]

Or alternatively, haproxy.

[kubo6472]

Or, or: https://sr.ht/~emersion/tlstunnel/

[FireMasterK]

Partially complete with 2480d0d, Caddy is still left.

We should use the inbuilt cache directive: https://github.com/caddyserver/cache-handler

[kubo6472]

{
    order cache before rewrite
    cache
}

example.com {
    cache {
      stale 10s
      ttl 10s
    }
    reverse_proxy your-app:8080
}

This is what I've managed to splice together based on that doc you linked. No idea if it works as you want it to, but I think this is the way.

[FireMasterK]

Is it built by default? If not, I think a xcaddy build to use this