[docsy] New IA

[chalin]

Here's the current organization of pages under docs and my suggested rework:

✔️  Overview
✔️    Metadata   --> move to below `/docs` and ensure `title` is "Roles and Metadata" (drop `linkTitle`)
✔️    Project    --> move to below `/docs`
✔️      TAPs     --> move back under /community
✔️    Security   --> move to below `/docs` 
✔️  Get started  --> rename to "Getting started"
✔️    Adopter     --> fold content into Getting started
✔️    Contributor --> move to Contributing under `/docs`
✔️  History       --> move to below `/about` or `/docs/project`
✔️  Timeline      --> move to below `/about` or `/docs/project`
✔️  FAQ

Note:

• The security audits page should be moved under /resources

Tasks

• [docsy] Move TAPs back under Community and copyedit #95
  • Copyedit the TAPs page #80
• [docsy] Recover missing security pages and create Security section #96
  • [docsy] Recover security audits page #94
• [docsy] Create Project section under docs #97
• [docsy] Promote Metadata section to top-level docs #98
• [docsy] Add Contact section #99
• [docsy] Streamline and refactor Getting started section #100

Issues transferred from

• Move TAP page to be under Community Dindihub/docsy-tuf.io#29
• New IA for docs Dindihub/docsy-tuf.io#31

Other

• [docsy] Recover security audits page #94