better consistency, add dotfiles for takamaki and new features

modules/global/options.nix

@@ -19,9 +19,7 @@
       };
 
       components.bootLoader = lib.mkOption {
-        type = lib.types.enum (map (name: lib.removeSuffix ".nix" name) (
-          builtins.attrNames (builtins.readDir "${self}/modules/components/boot-loaders")
-        ));
+        type = inputs.helpers.mkEnumFromDirContents "${self}/modules/components/boot-loaders";
         default = "grub";
       };