Allow for built markup in code demos

## Problem

Some applications have legacy code that isn't using Vue, but Vue compiles down to html. In that case, it is desirable to see the output html as well as the Vue.js code. That way, the non-Vue portions of the app can still use the design system.

## Task
- Add some kind of selector for choosing which markup you're viewing.
- Add a button to copy the code. 