[RFC]: add a GitHub workflow which prevents contributors opening dozens of PRs

[Planeshifter]

This PR proposes adding a GitHub workflow which "rate limits" contributors racing to open up dozens of PRs.

Namely, on an opened pull request,

• Check whether the pull request links to an open issue.
• If yes, check whether the issue has a "Good first issue" label. If no, exit.
• If yes, check whether the contributor has opened other PRs linked to good first issues. If no, exit.
• If yes, check whether the number of good first issue PRs exceeds a threshold. If no, exit.
• If yes, post a comment to the most recent PR saying "Hey, we noticed that you've been opening a number of PRs addressing good first issues. Thanks for your interest and enthusiasm. Now that you've made a few contributions, we suggest no longer working on good first issues and instead working on more involved tasks. Not only does this ensure that other new contributors can work on things, but it ensures you can spend your time on more challenging problems." <= or something to this effect.

Time estimate without AI: 2h
Time estimate with AI: 1h

[Planeshifter]

PR-URL: stdlib-js/stdlib#5500

Initial time to completion: 1h 8min

Additional time: 4min (fix in stdlib-js/stdlib@c5a083f)

Loom Recording:
https://www.loom.com/share/deaa0409cfad4152b4d30ece8e3ce48b?sid=e08619d9-5da2-46fd-b2ab-1643ba48d9bf

[Planeshifter]

Notes: this was mostly alright without AI. I struggled again a little with figuring out the jq command I needed, but otherwise was fairly straightforward as I was able to copy & paste a bunch and the task became significantly easier due to the earlier new feature of auto-assignment of "Good First PR" labels.