feat: add rate limiting Octokit plugin

[erezrokah]

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Fixes ##1503 🦕
Also related to #1440.
Could replace #1504

This PR adds the recommended throttling plugin, see https://octokit.github.io/rest.js/v19#throttling.

This probably needs more testing and consideration before merging as it can have a big impact. Opening for feedback.
I can follow up on the failing tests if maintainers think this is a good approach

[erezrokah]

Maybe we can put this behind an option so the default behavior is the same

[chingor13]

I would prefer if we dependency inject the configured octokit APIs rather than trying to configure it here. This would let the caller use any octokit plugins without our GitHub class needing to understand every configuration option.

For example, in the GitHub app we run, we provide an authenticated Octokit instance created by probot. This would mean the instantiator of the GitHub wrapper instance would need to configure the throttle plugin. Within this repo, it would mean configuring it only in the CLI.

[erezrokah]

Going to close as stale and I'll re-open once I have time to address the comments