porthos: split into modules

I have separated the modules into host-specific settings, and generic
settings that ought to be shared by every host.

I only have the 'porthos' host for now, but intend to also add my laptop
'aramis' at some point to this repository.

modules/default.nix

@@ -0,0 +1,11 @@
+# Common modules
+{ ... }:
+
+{
+  imports = [
+    ./language.nix
+    ./nix.nix
+    ./packages.nix
+    ./users.nix
+  ];
+}

modules/language.nix

@@ -0,0 +1,7 @@
+# Language settings
+{ ... }:
+
+{
+  # Select internationalisation properties.
+  i18n.defaultLocale = "en_US.UTF-8";
+}

modules/nix.nix

@@ -0,0 +1,11 @@
+# Nix related settings
+{ pkgs, ... }:
+
+{
+  nix = {
+    package = pkgs.nixFlakes;
+    extraOptions = ''
+      experimental-features = nix-command flakes
+    '';
+  };
+}

modules/packages.nix

@@ -0,0 +1,16 @@
+# Common packages
+{ pkgs, ... }:
+
+{
+  # List packages installed in system profile. To search, run:
+  # $ nix search wget
+  environment.systemPackages = with pkgs; [
+    git
+    git-crypt
+    mosh
+    vim
+    wget
+  ];
+
+  nixpkgs.config.allowUnfree = true; # Because I don't care *that* much.
+}

modules/users.nix

@@ -0,0 +1,25 @@
+# User setup
+{ config, ... }:
+let
+  my = config.my;
+in
+{
+  users.mutableUsers = false; # I want it to be declarative.
+
+  # Define user accounts and passwords.
+  users.users.root.hashedPassword = my.secrets.users.root.hashedPassword;
+  users.users.ambroisie = {
+    hashedPassword = my.secrets.users.ambroisie.hashedPassword;
+    description = "Bruno BELANYI";
+    isNormalUser = true;
+    extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
+    openssh.authorizedKeys.keys = with builtins; let
+      keyDir = ../ssh;
+      contents = readDir keyDir;
+      names = attrNames contents;
+      files = filter (name: contents.${name} == "regular") names;
+      keys = map (basename: readFile (keyDir + "/${basename}")) files;
+    in
+    keys;
+  };
+}