* [WIP] Refactor-docs-structure

* [Docs] Check link and fix rst  (#498)

* check link

* fix rst

* Fix conf.py

* Fix lint

* minor refine

* minor refine

* modify zh_readme and index.rst

* add migration exampls get_started design to en

* add tutorials to en

* correct chinese doc link

* Apply suggestions from code review

* Update docs/en/advanced_tutorials/distributed.md

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

Co-authored-by: Mashiro <57566630+HAOCHENYE@users.noreply.github.com>

* first commit

* tmp commit

* tmp commit

* tmp

* finish base module

* tmp commit

* tmp commit

* first finish

* minor refine

* clean the code

* delete design

* refine

* minor refine

* fix as comment

* fix as comment

* refine from jupyter notebook

* minor refine

* split model.md to model.md and initialize.md

* minor refine

* minor refine

* make link availiable

* fix as chengqi comment

* fix as chengqi comment

* fix link

* fix as wenwei comment

* Fix as comment

* Fix as comment

* Fix lint