* [Enhance] Remove unnecessary calls to speed import performance

* lazily import matplotlib

* minor refinement

* 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

* try to fix lint

* upgrade yapf version

* use another way to bypass yapf

* update docstring

* [Feature]: Add optimzier and constructor.

* refactor unit tests

* add optimizer doc

* add parrots wrapper

* add parrots wrapper

* solve comments

* resolve comments