Add proto-template with top-nav

[oubiwann]

• - Find or create a straight-up HTML + CSS Bootstrap example of this
• - Make it top-sticky
• - Theme it the way we want (see issue Update CSS #7)
• - Define top-nav menu items

[oubiwann]

Nav item data has been added as configurable data. Functions need to be written that generate actual HTML menus (using the new features in Exemplar). Then write a top-nav only HTML file that demonstrates this.

Then tweak with with Bootstrap hijinx to stick to the top of the page.

[oubiwann]

Sticky header navbar:

• https://getbootstrap.com/examples/navbar-fixed-top/

[oubiwann]

I've:

• added this example to the static content
• updated it to use the latest theme colors (from ticket Update CSS #7)

[oubiwann]

This task is done.