[Add] - Add a table of contents

[chg0901]

Create a table of contents below Related Works for the different levels of headings in a document. such as

Related Works

1. Diffusion Models
2. Diffusion Transformer
3. Baseline Video Generation Models
4. .....

The link should also be added for English and Chinese README files [Note that, the links for them are different], for example.

In README.md, add https://github.com/mini-sora/minisora#diffusion-models

1. Diffusion Models

In README_zh-CN.md, add https://github.com/mini-sora/minisora/blob/main/README_zh-CN.md#diffusion-model

1. Diffusion Models

You can find the link when you check the websit in the front of <h3> tags

[BaiYu96]

I get it