[MAINT] Update to new Python and dev tools

[adam2392]

Thanks for contributing. If this is your first time,
make sure to read contributing.md

PR Description

• Ran black
• Renamed docs/ -> doc/
• Setup pyproject.toml
• Updated min Python version to 3.8 - 3.11
• Updated GH actions and circleCI workflows

Merge checklist

Maintainer, please confirm the following before merging:

• All comments resolved
• This is not your own PR
• All CIs are happy
• PR title starts with [MRG]
• whats_new.rst is updated
• PR description includes phrase "closes <#issue-number>"

[adam2392]

@drammock @larsoner any chance either of you know how to get the circleCI to be able to git pull from this repo? This works fine on mne-icalabel and mne-connectivity.

[larsoner]

Looks like https://discuss.circleci.com/t/git-github-com-permission-denied-publickey-on-repo-that-previously-worked/37763

[larsoner]

I followed the advice in that thread, namely clicking "Stop Building" in the project in the CircleCI project settings page, then re-added it under the "projects" tab of the mne-tools org on CircleCI and now the checkout step succeeds. I'll let you continue :)

[adam2392]

@pmyers16 can you add an entry here for you?