Add on_thread_start_hook

[binarygit]

Description

This PR closes #3192

It provides a before_thread_start hook which can be used to execute code before a thread starts.

Your checklist for this pull request

• I have reviewed the guidelines for contributing to this repository.
• I have added (or updated) appropriate tests if this PR fixes a bug or adds a feature.
• My pull request is 100 lines added/removed or less so that it can be easily reviewed.
• If this PR doesn't need tests (docs change), I added [ci skip] to the title of the PR.
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• I have updated the documentation accordingly.
• All new and existing tests passed, including Rubocop.

[binarygit]

I closely followed @biinari's work on #2920 and I think I have done it correctly but please let me know if I missed something 🙏

[nateberkopec]

Hey @binarygit, thanks for answering the call and thanks for your first contribution 😄

[dhavalsingh]

turbo-rails / ubuntu-22.04 Ruby head Rails 7.0 (pull_request) Failing after 2m

This test is failing. Will this PR get merged as it is or can I help so this test also passes?

First time contributing hence the doubt, sorry if it's a basic query.