enable garbage collection, openssh, autologin, etc.

also:
- mangohud
- flatpak
- wake on lan
- increase mic gain

global-default.nix

@@ -19,6 +19,12 @@ in {
     "flakes"
   ];
 
+  nix.gc = {
+    automatic = true;
+    persistent = true;
+    dates = "Sun 05:00";
+  };
+
   boot.loader.efi.canTouchEfiVariables = true;
 
   networking.networkmanager.enable = true;
@@ -57,6 +63,7 @@ in {
     fzf
     jq
     busybox
+    ethtool
   ];
 
   programs.nano = {