Getting more idomatic nix modules setup... will tackle users dir later

modules/boot/grub.nix

@@ -0,0 +1,31 @@
+{
+  config,
+  lib,
+  ...
+}:
+with lib;
+let
+  name = "boot_grub";
+  cfg = config.mods.${name};
+in
+{
+  options = {
+    mods.${name} = {
+      enable = mkEnableOption (lib.mdDoc "Enable ${name}");
+      device = mkDefaultOption {
+        type = types.str;
+        default = "/dev/sda";
+        description = ''
+          The device to install GRUB on.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    boot.loader.grub = {
+      enable = true;
+      device = cfg.device;
+    };
+  };
+}

modules/boot/systemd.nix

@@ -0,0 +1,31 @@
+{
+  config,
+  lib,
+  ...
+}:
+with lib;
+let
+  name = "boot_systemd";
+  cfg = config.mods.${name};
+in
+{
+  options = {
+    mods.${name} = {
+      enable = mkEnableOption (lib.mdDoc "Enable ${name}");
+    };
+  };
+
+  config = mkIf cfg.enable {
+    # Use the systemd-boot EFI boot loader.
+    boot.loader = {
+      systemd-boot = {
+        enable = true;
+        consoleMode = "keep";
+      };
+      timeout = 5;
+      efi = {
+        canTouchEfiVariables = true;
+      };
+    };
+  };
+}