Add custom error pages and Nginx configuration for proxy module

- Introduced custom HTML error pages for various HTTP status codes (400, 401, 403, 404, 408, 429, 500, 502, 503, 504) in the proxy module.
- Created a .gitignore file to exclude non-HTML files in the error resources directory.
- Updated Nginx configuration to serve custom error pages for upstream errors.
- Added new Nginx configuration templates for handling HTTP and stream protocols.
- Implemented Wireguard configuration templates and associated variables for secure connections.
- Established Kubernetes resources for Stunnel and Wireguard, including deployment, service accounts, and config maps.
- Defined variables for the Stunnel and Wireguard modules to facilitate configuration.
- Created a new Wol Proxy module with Kubernetes resources for deployment and service management.

terraform/modules/utils/prometheus/config.tf

@@ -0,0 +1,17 @@
+locals {
+  app_version = var.tag
+  data_folder = "${var.persistent_folder}/prometheus"
+
+  prometheus_config          = coalesce(var.config, file("${path.module}/resources/default.yml"))
+  prometheus_config_checksum = md5(local.prometheus_config)
+
+  prometheus_rules = yamlencode({
+    groups = [
+      {
+        name  = "custom-rules"
+        rules = var.rules
+      }
+    ]
+  })
+  prometheus_rules_checksum = md5(local.prometheus_rules)
+}