home: create 'modules/home' folder

Consolidating all modules under the same path, to clear out the
top-level directory.

modules/home/x/keyboard/default.nix

@@ -0,0 +1,12 @@
+{ config, lib, ... }:
+let
+  cfg = config.my.home.x;
+in
+{
+  config = lib.mkIf cfg.enable {
+    home.keyboard = {
+      layout = "fr";
+      variant = "us";
+    };
+  };
+}