feat: added default boot modes

modules/boot.nix

@@ -0,0 +1,35 @@
+{
+  config,
+  lib,
+  ...
+}: {
+  option.boot.mode = lib.mkOption {
+    description = "Enable recommended Options for different boot modes";
+    type = lib.types.nullOr (lib.types.enum ["bios" "efi" "secureboot"]);
+    default = null;
+  };
+  config = let
+    bios-conf = {
+      boot.loader.grub = {
+        enable = true;
+        efiSupport = false;
+        configurationLimit = 32;
+      };
+    };
+    efi-conf = {
+      # Use the systemd-boot EFI boot loader.
+      boot.loader = {
+        systemd-boot.enable = true;
+        systemd-boot.configurationLimit = 32;
+        efi.canTouchEfiVariables = true;
+      };
+    };
+  in
+    lib.mkIf (config.boot.mode != null)
+    {
+      "efi" = efi-conf;
+      "bios" = bios-conf;
+      "secureboot" = throw "not yet implemented";
+    }
+    .${config.boot.mode};
+}