Add a possibility to change the size of the icon added to ToolButton with iconSource Qml

Please add a possibility to change the size of the icon added to the Qml ToolButton with iconSource. Most of the users do not want to deal with the ButtonStyle just for the sake of changing the size of the icon.

Use of the Image is not appropriate in current situation, because such simple things as tool button's look on disabled and on clicked will be broken.