Clean up all the Modifiers that take in a string value, providing a richer API instead

[bitspittle]

See :frontend:kobweb-compose com.varabyte.kobweb.compose.ui.modifiers

For example, Modifier.background(value: String) is fragile and forces users to look up the CSS APIs online. e.g. https://developer.mozilla.org/en-US/docs/Web/CSS/background

Instead, we should provide richer APIs across the board. If users want to use the text version, they can always do:

Modifier.styleModifier {
  background(String)
}

This should be done before 1.0 launches, because after that, the API is forever.

Note: We should provide @Deprecated versions of any old stringly-typed to not break users for now but they should be aware that they will be gone by 1.0.