* [Docs] Add readthedocs.yml

* include torch in readthedocs.yml

* add torch torchvision in docs.txt

[Refactor]: migrate LMDB backends and modifications from open-mmlab/mmcv#1764 and  open-mmlab/mmcv#1747 (#426)

* Add fileio ut

* pick modification from master branch

* pick modification from mmcv #1764

* test fileio without mmcv

* remove unnecessary checking

* add required lib for vis

* fix comment

* first commit

* update logging

* update MessageHub unit test and LogBuffer unitest

* update logging docs

* update logging impl and test

* update test logging

* update test

* update logging test and impl

* Fix logging test

* Update log_buffer.py

* rename statistics argumentes

* fix as comment

* Fix as comment

* Fix as comment

* Fix as comment

* Fix meta class

* Fix as comment

* Fix as comment

* Fix as comment

* Fix name declare

* Fix as comment

* Fix as comment

* Fix as comment

* Fix docstring

* Fix as comment

* Fix as comment

* [Docs] Configure the documentation

* delete mypy.ini