Update Component: Navigation - enable mega nav

[joesnellpdx]

Either enable a meganav option for the navigation component

Describe the solution you'd like
@saltcod Please add acceptance / expectations

• links to examples
• options to consider
• depth of content
• how complex does it need to be?

Describe alternatives you've considered
If needed, a new meganav component is a possible solution - but not ideal.

Please see #45 and other navigation component issues before starting.