Add minimal modular setup

modules/nixos/core/boot.nix

@@ -0,0 +1,4 @@
+{ pkgs, lib, ... }: {
+  boot.loader.systemd-boot.enable = true;
+  boot.loader.efi.canTouchEfiVariables = true;
+}

modules/nixos/core/default.nix

@@ -0,0 +1,7 @@
+{ pkgs, lib, ... }: {
+  imports = [
+    ./boot.nix
+    ./network.nix
+    ./user.nix
+  ];
+}

modules/nixos/core/network.nix

@@ -0,0 +1,5 @@
+{ pkgs, lib, ... }: {
+  config = {
+    networking.networkmanager.enable = true;
+  };
+}

modules/nixos/core/user.nix

@@ -0,0 +1,16 @@
+{ pkgs, lib, config, ... }: {
+  options = {
+    mods.user.name = lib.mkOption {
+      default = "muon";
+      description = "username of the main system user";
+    };
+  };
+
+  config = {
+    users.users.${config.mods.user.name} = {
+      isNormalUser = true;
+      extraGroups = [ "wheel" ];
+      initialPassword = "changeme";
+    };
+  };
+}