GitLab

* [Docs] Refactor the structure of documentation

* [Docs] Refactor the structure of documentation

* fix symlink

* fix link

* fix typo

* polish docstring

* fix docstring

* [Docs] Use PyTorch sphinx theme

* add sphinx-copybutton

* add twitter and zhihu link

* remove shpinx_rtd_theme from doc.xtx

* update docs.txt

* update conf.py