Support five levels of nested items in the global nav
Right now, we may nest up to 3 items in the global nav. We have 3 items (top to bottom):
- section_title
- category_title
- doc_title
We should make this more generic, so that we can nest as many items as we want (five being a good amount).
For example, Docker has generic items that they can nest indefinitely:
- sectiontitle:
section:
- path:
title:
- sectiontitle:
section:
- title:
path:
- sectiontitle:
section:
- sectiontitle:
section:
- path:
title: