chore: Restructured infra modules

infra/modules/network/outputs.tf

@@ -0,0 +1,9 @@
+output "id" {
+  value = hcloud_network.main.id
+}
+
+# Exposed so dependents can depend_on the subnet existing, not just the network -
+# attaching a server to a network fails if the network has no subnet yet.
+output "subnet_id" {
+  value = hcloud_network_subnet.main.id
+}