* set _is_init to True when pretrained is True

* fix comments

* fix unit test install mmdet and mmcls

* raise error when mmdet is not installed

* rename check_and_install to install_package

* split test case

Co-authored-by: C1rN09 <zhaoqian@pjlab.org.cn>

* 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