Feat: support balanced dataset to speed-up training

[yqyao]

Balanced Dynamic Mini-Batch for paper OmniBal: Towards Fast Instruct-tuning for Vision-Language Models via Omniverse Computation Balance.

Original Repo: https://github.com/ModelTC/OmniBal

[czczup]

Hello, thank you for contributing to our repository. We will proceed with the merge after conducting some tests. Thanks again!