Layer component / contextual tokens

[gregorw]

In v11 Carbon Design System introduced contextual tokens. This is something we wanted to use before using Svelte components. This would make the light prop obsolete.

What it means is that we added a Layer component as described in the link above.

<Layer>
  <ChildComponent />
  <Layer>
    <ChildComponent />
    <Layer>
      <ChildComponent />
    </Layer>
  </Layer>
</Layer>

I'm not exactly sure how hard it would be. It probably requires to use contextual tokens in most of the components. I also wonder whether there is any interference with inline theming and the Theme component.

[gregorw]

See #1253