Move all of NixOS to nixos/ in preparation of the repository merge

nixos/modules/misc/passthru.nix

@@ -0,0 +1,15 @@
+# This module allows you to export something from configuration
+# Use case: export kernel source expression for ease of configuring
+
+{ config, pkgs, ... }:
+
+{
+  options = {
+    passthru = pkgs.lib.mkOption {
+      description = ''
+        This attribute set will be exported as a system attribute.
+        You can put whatever you want here.
+      '';
+    };
+  };
+}