Move configuration of servers completely to ansible

With this change we no longer use user-data scripts on the provided
machines. That makes it way easier for me to handle all the
configuration, since I only have to run ansible. Furthermore this the
burdon to think what may went wrong, since ansible is easier to debug
than some arbitrary scripts which run at provisioning-time on the
machines.

With this change I should also think about restructuring the code a bit
as well. Since it's actually easier to provide the initial
software-stack for the cluster via ansible than via terraform, at least
as far as I can tell right now.

infra/modules/hetzner/kubernetes/outputs.tf

@@ -9,3 +9,11 @@ output "server_ips_v6" {
 output "agent_ips_v4" {
   value = flatten([for key, value in hcloud_server.agent : value.network.*.ip])
 }
+
+output "private_network_cidr" {
+  value = local.network
+}
+
+output "private_network_nat" {
+  value = cidrhost(local.subnet_eu_central, 1)
+}