Add subproject governance

[bupd]

Adds lightweight Harbor subproject governance and records Harbor CLI as an active Harbor subproject.

Why

Harbor has subprojects with their own maintainers, but the community repo does not currently document scoped subproject reviewer/maintainer roles under the Harbor project. This makes subproject ownership visible without changing the existing Harbor Maintainer election process.

Prior art

This follows common governance patterns used by CNCF projects:

• Kubernetes documents SIGs, subprojects, reviewers, approvers, and subproject owners:
  • https://github.com/kubernetes/community/blob/main/governance.md
  • https://github.com/kubernetes/community/blob/main/community-membership.md
• CNCF's project template includes dedicated subproject governance guidance:
  • https://github.com/cncf/project-template/blob/main/GOVERNANCE-subprojects.md
• OpenTelemetry defines maintainers as scoped technical authorities for subprojects:
  • https://github.com/open-telemetry/community/blob/main/guides/contributor/membership.md
• Prometheus ties maintainership to individual projects or parts of projects:
  • https://prometheus.io/governance/
• Backstage uses project areas with scoped maintainers and self-governing ownership areas:
  • https://github.com/backstage/community/blob/main/GOVERNANCE.md
• containerd distinguishes core and non-core subprojects, with subproject-specific maintainer lists and scoped responsibility:
  • https://github.com/containerd/project/blob/main/GOVERNANCE.md
• Envoy records scoped maintainers/code owners for areas such as Envoy Mobile and extensions:
  • https://github.com/envoyproxy/envoy/blob/main/OWNERS.md

This keeps the Harbor version intentionally small: scoped subproject reviewers/maintainers, subproject autonomy, MAINTAINERS.md as the community record, and no change to top-level Harbor Maintainer governance.

[NucleoFusion]

lgtm!

[qcserestipy]

lgtm

[wy65701436]

Thanks, @bupd I'll review this. Also, thank you for providing the examples from other CNCF projects—they are really helpful for understanding how we can organize our subprojects and roles.

[wy65701436]

I would like to hold off on merging this to allow more maintainers to review it, especially since there are changes to the GOVERNANCE file.

[wy65701436]

https://github.com/goharbor/acceleration-service

the acceleration-service can also be added, thanks.