Rapid-latex-ocr

- 将相关的ONNX模型文件改为在运行时自动下载到安装目录下
- 添加模型转换仓库

- ⚠️This release used to store the onnx model and json files.
- the directory of **models.zip** is following:
text
models
├── decoder.onnx
├── encoder.onnx
├── image_resizer.onnx
└── tokenizer.json