Migrate all service modules from nginx-ingress to Traefik

- Remove nginx-specific ingress variables (use_proxy_protocol, proxy_timeout, additional_configuration_snippet)
- Update ingress annotations to use Traefik middleware CRDs
- Delete nginx-ingress module (replaced by traefik)
- Add new traefik middleware.tf for shared middleware definitions
- Update service modules to work with new ingress_factory interface

modules/kubernetes/hackmd/main.tf

@@ -150,7 +150,4 @@ module "ingress" {
   namespace       = kubernetes_namespace.hackmd.metadata[0].name
   name            = "hackmd"
   tls_secret_name = var.tls_secret_name
-  extra_annotations = {
-    "nginx.ingress.kubernetes.io/proxy-body-size" : "20000m"
-  }
 }