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

nixos/modules/system/boot/loader/raspberrypi/raspberrypi.nix

@@ -0,0 +1,38 @@
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  builder = pkgs.substituteAll {
+    src = ./builder.sh;
+    isExecutable = true;
+    inherit (pkgs) bash;
+    path = [pkgs.coreutils pkgs.gnused pkgs.gnugrep];
+    firmware = pkgs.raspberrypifw;
+  };
+
+  platform = pkgs.stdenv.platform;
+
+in
+
+{
+  options = {
+
+    boot.loader.raspberryPi.enable = mkOption {
+      default = false;
+      description = ''
+        Whether to create files with the system generations in
+        <literal>/boot</literal>.
+        <literal>/boot/old</literal> will hold files from old generations.
+      '';
+    };
+
+  };
+
+  config = mkIf config.boot.loader.raspberryPi.enable {
+    system.build.installBootLoader = builder;
+    system.boot.loader.id = "raspberrypi";
+    system.boot.loader.kernelFile = platform.kernelTarget;
+  };
+}