GitLab

* update master branch to main

* added FAQ about updating the branch from master to main

* fixed some false positive correction

* added what is new section

* fixed the quoted code area

* added release what is new section

* added a step in release.md

* fixed a word

* add tutorials

* add new context, modify and delete existing docs

* remove duplicate labels

* modify layout and more nits

* address comments

* fix merge conflicts

* [docs]: add checkpoint_wrapper and many small fixes

* update copyright year

Also updated canonical_url to be fairscale.
Also removed unnecessary htmi_theme_path.