Write docs/* utility pages

[michaelsena]

• Project:
  - docs/project/index.md
  - Roadmap: docs/project/roadmap.md
  - Governance: docs/project/governance.md
  - Code of Conduct: docs/project/code-of-conduct.md
  - Security Issues: docs/project/security-issues.md
• Community:
  - docs/community/index.md
  - Ways to contribute: docs/community/how-to-contribute.md
  - Chat & discussion forums: docs/community/chat-and-discussion-forums.md
  - Social media: docs/community/social-media.md