nixos-module/defaults: install iftop

nix/nixos-module/defaults.nix

@@ -32,7 +32,7 @@
 
   environment.systemPackages = with pkgs; [
     vim screen git wget psmisc
-    tcpdump iputils mtr traceroute bmon iptables conntrack-tools
+    tcpdump iputils mtr traceroute bmon iptables conntrack-tools iftop
     bridge-utils dhcpcd ethtool
   ];