Possible Hetzner infra improvements

Looking at the current hetzner setup, a few things stand out:

• On prod, we've got 2 load balancers defined. I'd think we only need 1, so please kill the other. https://console.hetzner.com/projects/11727494/loadbalancers Thing is, they cost twice the price per month of our servers. So it only makes sense to keep it for the workers, not the control plane. If it's supposed to be there because it came as a default, please describe it in the infra readme and perhaps give it a better name.
• Our servers have ipv4 IPs assigned. They're not exposed to the world, because they're behind a load balancer that has the public ipv4 address. also the control plane would be fine on only ipv6. Saves some costs (we pay per ipv4) and don't contribute to taking more scarce ipv4 out of the pool for no reason.
• Update infra docs to make sure this knowledge gets integrated in the setup docs.