Addon-docs: Collaborators doc block

[shilman]

Doc block to show collaborators for a component and related metadata:

• user id
• avatar
• contact?
• commit history summary? (num commits? last committed?)

[github-actions[bot]]

Automention: Hey @elevatebart @JeroenReumkens, you've been tagged! Can you give a hand here?

[shilman]

Converting this to a discussion. We’re reserving feature issues for things that are on our short-term roadmap. We’ll check back periodically to see whether this is a good candidate to be added. If this feature would be useful to you, please upvote!