* [Enhance] Enhance revert_sync_batchnorm and convert_sync_batchnorm

* [Enhance] Enhance revert_sync_batchnorm and convert_sync_batchnorm

* Fix unit test

* Add coments

* Refine comments

* clean the code

* revert convert_sync_batchnorm

* revert convert_sync_batchnorm

* refine comment

* fix CI

* fix CI

* Add runner test cast

* Fix unit test

* fix unit test

* pop None if key does not exist

* Fix is_model_wrapper and force register class in test_runner

* [Fix] Fix is_model_wrapper

* destroy group after ut

* register module in testcase

* fix as comment

* minor refine

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

* fix lint

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

* [Feature] Support convert BN to SyncBN by config

* make unit test compatible with cpu

* Fix as comment

* fix unit test

* change signature of convert_sync_batchnorm: rename sync_bn to implemention

* fix unit test

* fix unit test

* regist pytorch ddp and dp, add unit test

* minor refine

* Support check custom wrapper

* enhance ut

* Rename data to structure

* adjust the way to import module

* adjust the way to import module

* rename Structure to Data Structures in docs api

* rename structure to structures

* support using some modules of mmengine without torch

* fix circleci config

* fix circleci config

* fix registry ut

* minor fix

* move init method from model/utils to model/weight_init.py

* move init method from model/utils to model/weight_init.py

* move sync_bn to model

* move functions depending on torch to dl_utils

* format import

* fix logging ut

* add weight init in model/__init__.py

* move get_config and get_model to mmengine/hub

* move log_processor.py to mmengine/runner

* fix ut

* Add TimeCounter in dl_utils/__init__.py

* [Feat] Support revert syncbn

* use logger.info but not warning

* fix info string