Totally refactor HTML structure of dropdown view controllers

The current HTML inside the div.extension for dropdown view controllers is ANCIENT!

This needs to be redone completely to inherit styling from the now established HTML/CSS frameworks.

Doing that would also get rid of the legacy button design we now see in them as well as finally re-enable helper hooks for embedded forms.

Special care has to taken here to still get super-special elements working like color choosers and stuff.