add Sequence Parallelism

[HaoshengZou]

What does this PR do?

add Sequence Parallelism (#4733 #5024 #5207 #5815 #5841 etc.) direct plug&play use at https://github.com/Qihoo360/360-LLaMA-Factory

We have a separate README and chat-group at https://github.com/Qihoo360/360-LLaMA-Factory, only for Sequence Parallelism part. They are not to be merged. We developed based on LLaMA-Factory's latest release v0.9.1. We also based on https://github.com/zhuzilin/ring-flash-attention. The original repos are fully acknowledged. We developed this at 360. I am PhD from Tsinghua-CS Prof. Jun Zhu's group.

Feel free to review and comment on changes as you see fit. We'll make it better. Thank you!

Before submitting

• [x] Did you read the contributor guideline?
• [x] Did you write any new necessary tests?