Make the classification of API documentation suitable for API independent sphinx tree in enhanced paddlepaddle.org #8128
Description
Please adjust the classification of API documentation and make it suitable for API independent branch in enhanced paddlepaddle.org (调整API文档体系，适应优化后官网的API独立分支)
In the enhanced paddlepaddle.org, API documentation is an independent branch in the root navigation. Therefore, we decided to create a separated Sphinx index for API and we can simply link the root navigation to the generated content. To achieve this goal, we have to adjust the classification of API documentation and make it suitable for API independent branch in enhanced paddlepaddle.org firstly.
Thank you very much!
Project Background
Polish documentation of PaddlePaddle, enhancing user experience
-----Enhancement Plan:
Stage 1: https://note.youdao.com/share/?token=83F0AB634A7749E6B4676F823D6EC343&gid=69922175#/
-----Enhancement Schedule:
https://shimo.im/sheet/VnyT2IKRHjoU1a6i/6HGyl//