🪄`LivePreview` support

Live preview

To make it work with live preview you need to specify either all styles or exact autolayout's one

With all app styles included

class Welcome_Preview: WebPreview {
    override class var title: String { "Initial page" } // optional
    override class var width: UInt { 440 } // optional
    override class var height: UInt { 480 } // optional

    @Preview override class var content: Preview.Content {
        // add styles if needed
        AppStyles.all
        // add here as many elements as needed
        WelcomeViewController()
    }
}

With exact app styles including autoalyout's one

class Welcome_Preview: WebPreview {
    override class var title: String { "Initial page" } // optional
    override class var width: UInt { 440 } // optional
    override class var height: UInt { 480 } // optional

    @Preview override class var content: Preview.Content {
        // add styles if needed
        AppStyles.id(.mainStyle)
        AppStyles.id(.autolayoutStyles)
        // add here as many elements as needed
        WelcomeViewController()
    }
}