add miracast module

modules/programs/miracast.nix

@@ -0,0 +1,23 @@
+{ config
+, lib
+, pkgs
+, ...
+}:
+
+with lib;
+let
+  cfg = config.my.programs.miracast;
+in
+{
+  options.my.programs.miracast.enable = mkEnableOption "miracast";
+
+  config = mkIf cfg.enable {
+    networking.firewall = {
+      allowedTCPPorts = [ 7236 7250 ];
+      allowedUDPPorts = [ 7236 5353 ];
+    };
+    users.users.moritz.packages = with pkgs; [
+      gnome-network-displays
+    ];
+  };
+}