qt_common: Move window info function out of bootmanager

Function is useful outside of bootmanager, so put it in a common place.

qt_common: Add missing include

qt_common: Add some newlines

qt_common: Add trailing newline

qt_common: Add trainline newline

src/yuzu/qt_common.h

@@ -0,0 +1,15 @@
+// SPDX-FileCopyrightText: 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <QWindow>
+#include "core/frontend/emu_window.h"
+
+namespace YuzuQtCommon {
+
+Core::Frontend::WindowSystemType GetWindowSystemType();
+
+Core::Frontend::EmuWindow::WindowSystemInfo GetWindowSystemInfo(QWindow* window);
+
+} // namespace YuzuQtCommon