docs: Add TOC mentoring subproject charter

[bupd]

Summary

Add the TOC Mentoring SubProject charter and updates the metadata.

Changes

• Replace the placeholder in Mentoring SubProject charter with misson, scope, out-of-scope items, and deliverables
• Update tags.yaml with the Mentoring SubProject mission statement and leadership.
• Regenerated the Mentoring SubProject README from tags.yaml

cc ./ @nate-double-u , @Cali0707

[github-actions]

⚠️ README Files Should Be Updated via tags.yaml

The following TAG or TOC subproject README files have been directly edited:

• toc_subprojects/mentoring-subproject/README.md

These README files are auto-generated from the tags.yaml file using the generator script. Please update the tags.yaml file instead of editing the README files directly.

For more information on how to update these files, please see the generator README.

Once you update tags.yaml, the README files will be automatically regenerated by the existing automation workflow.

[cncf-automation-bot]

This PR has been superseded by PR #2219 and has been automatically closed.

[riaankleinhans]

@bupd the tags.yaml automation only allow for the tags.yaml to be updated in a PR.
Please submit the charter in a separate PR.

[bupd]

Thanks will do so.