Feature/add suport class and

[zhgchgli0718]

Support for Class/ID Style Mapping and Parsing

The class HTML attribute can use the HTMLTagClassAttribute to define classNames with pre-defined styles.

HTML allows specifying multiple class attributes separated by spaces, but the id attribute can only be assigned a single value per HTML tag.

e.g.:

<span id="header">hey</span>hey <span id="text-red text-small">Teste de texto text small</span> hey<span class="text-red">hey</span>heyhey

let parser = ZHTMLParserBuilder.initWithDefault().add(HTMLTagClassAttribute(className: "text-red", render: {
    return MarkupStyle(foregroundColor: MarkupStyleColor(color: .red))
})).add(HTMLTagClassAttribute(className: "text-small", render: {
    return MarkupStyle(font: MarkupStyleFont(.systemFont(ofSize: 6)))
})).add(HTMLTagIdAttribute(idName: "header", render: {
    return MarkupStyle(font: MarkupStyleFont(.systemFont(ofSize: 36)))
})).build()