DolphinQt: Move "Controllers" to main settings window.

Source/Core/DolphinQt/Config/ControllersPane.h

@@ -0,0 +1,23 @@
+// Copyright 2025 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <QWidget>
+
+class WiimoteControllersWidget;
+
+class ControllersPane final : public QWidget
+{
+  Q_OBJECT
+public:
+  ControllersPane();
+
+protected:
+  void showEvent(QShowEvent* event) override;
+
+private:
+  void CreateMainLayout();
+
+  WiimoteControllersWidget* m_wiimote_controllers;
+};