started modifing configuration structure

system/services/libvirtd/default.nix

@@ -0,0 +1,16 @@
+{ config, pkgs, ... }:
+{
+  virtualisation.libvirtd = {
+    enable = true;
+    allowedBridges = [
+      "virbr0"
+      "nm-bridge"
+    ];
+    qemu.package = pkgs.qemu_full;
+  };
+
+  environment.systemPackages = with pkgs; [
+    qemu-utils
+    virt-manager
+  ];
+}