Simplify widgets creation

[lucasvsme]

This PR adds a lambda to some widgets to avoid using the apply scope function to setup the instance created. It also has a default value so those who want to use apply anyway can do without problems.

Before

val button = Button(text = "Click").apply {
    action {
        println("Hello World")
    }
}

After

val button = Button(text = "Click") {
    action {
        println("Hello World")
    }
}