MAINTAINERS.md: maintainer list, responsibilities and emeritus process

[mwaldheim]

Goal

Formal maintainers file — checked by CLOMonitor, referenced by CNCF TOC during due diligence.

Contents

• Current maintainers: name, GitHub handle, affiliation, area of expertise
• Emeritus maintainers section
• How to add/remove maintainers (references GOVERNANCE.md)
• Review and merge rights per area (CODEOWNERS)

Tasks

• Create MAINTAINERS.md
• Create .github/CODEOWNERS referencing maintainers by GitHub handle
• Document the process to nominate new maintainers
• Ensure vendor diversity is documented (important for CNCF)