Replace dropdown in design system

[basmasking]

We have a dropdown in the design system with custom JavaScript. The new Popover api allows us to create the same experience without custom JavaScript.

[petermasking]

The Popover API is a great addition for building rich use experiences. Sadly we can't use it to replace the dropdown component yet because there's still an essential feature missing: the Anchor Position API. This API allows for easy positioning of the popup. For example, below the dropdown element.

I'll delete the experimental branch and put this issue on hold till better times.

[basmasking]

Firefox still doesn't support it. The other major browsers do, so we still need to wait for FF to implement it.