Set up a poll workflow for the maintainers team

[JohnTitor]

To make the consensus of the maintainers team, we currently create checkboxes manually and ping each people. But it's handsome and can easily miss a person.
I think this workflow should be automated and handled by a bot or GHA. That would be useful when we create multiple polls, actually, there are a lot of RFCs requiring a review.

Prior art: https://github.com/rust-lang/rfcbot-rs/