home: keyboard: extract from X module

This deserves to be its own standalone module, as I would want to use it
in both X and Wayland, etc...

modules/home/default.nix

@@ -23,6 +23,7 @@
     ./gtk
     ./htop
     ./jq
+    ./keyboard
     ./mail
     ./mpv
     ./nix

modules/home/keyboard/default.nix

@@ -1,8 +1,12 @@
 { config, lib, ... }:
 let
-  cfg = config.my.home.x;
+  cfg = config.my.home.keyboard;
 in
 {
+  options.my.home.keyboard = with lib; {
+    enable = my.mkDisableOption "keyboard configuration";
+  };
+
   config = lib.mkIf cfg.enable {
     home.keyboard = {
       layout = "fr";

modules/home/x/default.nix

@@ -3,10 +3,6 @@ let
   cfg = config.my.home.x;
 in
 {
-  imports = [
-    ./keyboard
-  ];
-
   options.my.home.x = with lib; {
     enable = mkEnableOption "X server configuration";
   };