Expand/collapse codeboxes

[ryancreatescopy]

Is your feature request related to a problem? Please describe.

Our codebox component can make our docs pages a little cumbersome, especially when we show an entire contract or a lot of code. We should introduce the ability to expand/collapse the codebox.

Describe the solution you'd like

The codebox should be collapsed by default. But the collapsed state should show a few lines of the code.

While adding the button to show/hide code, we should revisit the button design. The primary purple color can be a little harsh on the codebox background.

See problem below

[wackerow]

Working on this now