Simplify common imports

This shouldn't be an issue since I'd rather import all of these at once
than selectively import them.

common/default.nix

@@ -1,10 +1,38 @@
+{ pkgs, ... }:
+
 {
   imports = [
-    ./home-manager
-    ./locale
-    ./nix
-    ./systemd
-    ./timezone
     ./user
   ];
+
+  # locale
+  i18n.defaultLocale = "en_US.UTF-8";
+  i18n.supportedLocales =
+    [ "en_US.UTF-8/UTF-8" "ja_JP.UTF-8/UTF-8" "fr_FR.UTF-8/UTF-8" ];
+
+  # nix
+  nix = {
+    package = pkgs.nixFlakes;
+    settings = {
+      experimental-features = [ "nix-command" "flakes" ];
+    };
+  };
+
+  # home-manager
+  home-manager = {
+    useGlobalPkgs = true;
+    useUserPackages = true;
+
+    sharedModules = [{
+      home.stateVersion = "22.11";
+    }];
+  };
+
+  # systemd
+  systemd.extraConfig = ''
+    DefaultTimeoutStopSec=10s
+  '';
+
+  # timezone
+  time.timeZone = "America/New_York";
 }

common/home-manager/default.nix

@@ -1,10 +0,0 @@
-{
-  home-manager = {
-    useGlobalPkgs = true;
-    useUserPackages = true;
-
-    sharedModules = [{
-      home.stateVersion = "22.11";
-    }];
-  };
-}

common/locale/default.nix

@@ -1,5 +0,0 @@
-{
-  i18n.defaultLocale = "en_US.UTF-8";
-  i18n.supportedLocales =
-    [ "en_US.UTF-8/UTF-8" "ja_JP.UTF-8/UTF-8" "fr_FR.UTF-8/UTF-8" ];
-}

common/nix/default.nix

@@ -1,10 +0,0 @@
-{ pkgs, ... }:
-
-{
-  nix = {
-    package = pkgs.nixFlakes;
-    settings = {
-      experimental-features = [ "nix-command" "flakes" ];
-    };
-  };
-}

common/systemd/default.nix

@@ -1,5 +0,0 @@
-{
-  systemd.extraConfig = ''
-    DefaultTimeoutStopSec=10s
-  '';
-}

common/timezone/default.nix

@@ -1,3 +0,0 @@
-{
-  time.timeZone = "America/New_York";
-}