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/stunnel/config.tf

@@ -0,0 +1,20 @@
+locals {
+  wireguard_version = var.wireguard_version
+  wireguard_config = try(templatefile("${path.module}/resources/wireguard.conf.tpl", {
+    wireguard_private_key    = var.wireguard_config.private_key
+    wireguard_public_key     = var.wireguard_config.public_key
+    wireguard_pre_shared_key = var.wireguard_config.pre_shared_key
+    wireguard_address        = var.wireguard_config.address
+    wireguard_dns            = var.wireguard_config.dns
+    wireguard_allowed_ips    = join(", ", var.wireguard_config.allowed_ips)
+    wireguard_endpoint       = "${var.wireguard_config.endpoint}:${var.wireguard_config.endpoint_port}"
+  }), "null")
+  wireguard_config_checksum = nonsensitive(sha256(local.wireguard_config))
+
+  stunnel_version = var.stunnel_version
+  stunnel_config = templatefile("${path.module}/resources/stunnel.conf.tpl", {
+    local_targets  = var.local_targets
+    remote_targets = var.remote_targets
+  })
+  stunnel_config_checksum = sha256(local.stunnel_config)
+}