stonehenge: update config

hosts/stonehenge/default.nix

@@ -9,6 +9,11 @@
     # Include the results of the hardware scan.
     ./hardware-configuration.nix
     ./gitlab-runner.nix
+    ./nebula-vpn.nix
+    ./vagrant.nix
+
+    ../../system/sops.nix
+    ../../system/nix.nix
   ];
 
   # Bootloader.
@@ -95,6 +100,8 @@
 
   security.sudo.wheelNeedsPassword = false;
 
+  virtualisation.virtualbox.host.enable = true;
+
   # Install firefox.
   programs.firefox.enable = true;