Add support for MiniMax-M2

[rogeryoungh]

What does this PR do?

This PR adds MiniMax-M2 model to Hugging Face Transformers from MiniMaxAI.

Relevant Links:

• MiniMax M2 & Agent: Ingenious in Simplicity
• https://huggingface.co/MiniMaxAI/MiniMax-M2

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue or the forum? Please add a link
  to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

@ArthurZucker @Cyrilvallez

[molbap]

Very clean integration, no particular comments. Thank you! cc @Cyrilvallez for core review

[github-actions]

[For maintainers] Suggested jobs to run (before merge)

run-slow: auto, minimax_m2

[molbap]

Failing tests on the hub are unrelated timeouts. Thanks for the update!