[CI/Build] Add markdown linter

[rafvasq]

As a follow up to #10427 and related to #10366, this PR introduces markdown linting.

Rules currently modified in pyproject.toml:

• Disabled line-length, there are currently 2002 infractions.
• Disabled first-line-heading, because many docs use a sphinx-based heading target on the first line to cross-reference the page.
• Disabled no-inline-html, because HTML is used for superscripts on the supported models doc and comments elsewhere.
• Modified no-duplicate-headers so that it allows duplicate headers in different nests to accommodate pages like supported models, multi-modal inputs, openai server.

[github-actions]

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[DarkLight1337]

Is it possible to add this to format.sh so we can run this locally as well?

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @rafvasq.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @rafvasq.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[rafvasq]

@DarkLight1337 I've made some changes to a python-based linter so it's a more seamless change, similar to how sphinx-lint was being used before.

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @rafvasq.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[DarkLight1337]

Thanks for the cleanup!