Utils: Add AspectList::addToLayout

Added a new, clean IconButton that mimiks the ToolButton
with the compact/relaxed background.

Change-Id: I582c6aac404724af5459bab2ca9023aa63171f93
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/iconbutton.h

@@ -0,0 +1,27 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include "utils_global.h"
+
+#include <QAbstractButton>
+
+namespace Utils {
+
+class QTCREATOR_UTILS_EXPORT IconButton : public QAbstractButton
+{
+public:
+    IconButton(QWidget *parent = nullptr);
+
+    void paintEvent(QPaintEvent *e) override;
+    void enterEvent(QEnterEvent *e) override;
+    void leaveEvent(QEvent *e) override;
+
+    QSize sizeHint() const override;
+
+private:
+    bool m_containsMouse{false};
+};
+
+} // namespace Utils