DiT：Inference and Train

[wtomin]

What does this PR do?

Adds # (feature)

1. DiT model model definition in mindone/models/dit.py
2. Train and inference scripts for DiT model, using class labels as conditions.

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?
• [ ] Did you make sure to update the documentation with your changes? E.g. record bug fixes or new features in What's New. Here are the documentation guidelines
• [ ] Did you build and run the code without any errors?
• [ ] Did you report the running environment (NPU type/MS version) and performance in the doc? (better record it for data loading, model inference, or training tasks)
• [ ] 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.

@xxx

[zhtmike]

better to separated into two folder/PR if possible

[wtomin]

better to separated into two folder/PR if possible

Fixed.