Extend Maintainers

What

We want to extend the list of maintainers for the https://gitlab.com/gitlab-org/gitlab-vscode-extension/ repo.

Why

Currently we only have 1 maintainer for this project and this is a unsustainable bottle neck.

How

• Set a Q1 OKR for onboarding more maintainers
• Ping #frontend, #f_vscode_exension and #development
• Engage the current Frontend maintainers for support
• Engage the Editor team for support

We can lean on docs: update maintainer documentation (!643 - merged) as a beginning and our end goal should be between 4-10 maintainers.