Extracted from #72135.

• Removes drilldown navigation to reduce click fatigue and disorientation when moving between areas.
• Moves sub-navigation to tabs
  • Improves mobile accessibility as tabs remain reachable without having to open the main navigation drawer.
  • Important note: These are not a literal tabs pattern, they would be navigational and require a small new set of components (cc @aduth @mirka).

A little design work will be required to figure out which tabs make the most sense for the Patterns section which currently has many different pre-configured filters.