nixos/mdevctl: init module

nixos/modules/module-list.nix

···
   ./programs/less.nix
   ./programs/liboping.nix
   ./programs/light.nix
+  ./programs/mdevctl.nix
   ./programs/mosh.nix
   ./programs/mininet.nix
   ./programs/msmtp.nix

nixos/modules/programs/mdevctl.nix

···
+{ config, pkgs, lib, ... }:
+
+with lib;
+let
+  cfg = config.programs.mdevctl;
+in {
+  options.programs.mdevctl = {
+    enable = mkEnableOption (lib.mdDoc "Mediated Device Management");
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = with pkgs; [ mdevctl ];
+
+    environment.etc."mdevctl.d/scripts.d/notifiers/.keep".text = "";
+    environment.etc."mdevctl.d/scripts.d/callouts/.keep".text = "";
+
+  };
+}