also refactor nixos modules

modules/nixos/services/networking/caddy.nix

@@ -0,0 +1,42 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}: let
+  inherit (builtins) length;
+  inherit (lib) mkIf mkEnableOption mkOption types attrNames mapAttrs;
+
+  cfg = config.sneeuwvlok.services.networking.caddy;
+  hasHosts = (cfg.hosts |> attrNames |> length) > 0;
+  caddyPackage = pkgs.caddy.withPlugins {
+    plugins = ["github.com/corazawaf/coraza-caddy/v2@v2.1.0"];
+    hash = "sha256-pSXjLaZoRtKV3eFl2ySRSjl3yxi514G1Cb7pfrpxxtE=";
+  };
+in {
+  options.sneeuwvlok.services.networking.caddy = {
+    enable = mkEnableOption "enable caddy" // {default = true;};
+
+    hosts = mkOption {
+      type = types.attrsOf types.str;
+      default = {};
+    };
+
+    extraConfig = mkOption {
+      type = types.str;
+      default = "";
+    };
+  };
+
+  config = mkIf hasHosts {
+    services.caddy = {
+      enable = cfg.enable;
+
+      package = caddyPackage;
+
+      virtualHosts =
+        cfg.hosts
+        |> mapAttrs (host: extraConfig: {inherit extraConfig;});
+    };
+  };
+}