Add font icons support for QQC2 Buttons

What I want is essentially:

    Button {
        text: "Button"
        icon.font: myMaterialIcnoFont.name
        icon.content: MaterialSymbols.Icons.Delete
    }

Using 1000 different icons instead of a single font is awful to work with. It is also way harder to acquire a flat list of icons of any website than a simple iconfont. This test project uses icon fonts for regular text:

But it is currently not possible to set this for buttons and other places where icons are required. I know that a Button has icon.name that queries the icon from a QIcon::Theme, but this is just as bad as using hundreds of icons inside a folder.

MaterialSymbolFontTest.zip