Update overview landing pages to align with new nav

[edonehoo]

trafficstars

Update the existing overview pages for each major website section to provide additional context for the section and ensure accuracy within the new nav structure. For example, under Extensions, Patterns, and so on.

Needed for these nav sections:

• Releases (new top-level item)
• Components ? (determine if this makes sense / how to balance the all components gallery)
• Patterns (update existing)
• Extensions (update existing)
  • ChatBot (update existing)
  • Component groups (update existing)
  • Topology (add)
  • Catalog view (add)
• Foundations
  • Design tokens (update existing)
• Content (update existing)
• Accessibility (update existing)
• AI (update existing)
• Developer guides (add)
• Get involved / Contribute (add)