GitLab

* add tutorials

* add new context, modify and delete existing docs

* remove duplicate labels

* modify layout and more nits

* address comments

* fix merge conflicts

* rename files

* add newly renamed file

* rename and move checkpoint activations related files

* add test files to ci list

* fix lint errors

* modify docs

* add changelog

* retain old path for now

* fix lint errors

* add another import test case

* fix merge conflict

* add missing test file

* Document FSDP tips and tricks in a separate file

* [docs]: add checkpoint_wrapper and many small fixes

* update copyright year

* rewrite using autograd and Variable execution queue to make the reduce automatic
* share buckets with OSS to remove duplication
* some speed still likely on the table since the speed vs. bucketing does not match expectations, could be a follow up

* various fixes, no more issues with `make html` and more API fields should be populated