* [Feature] Support getting model from the name defined in the model-index file.
* Add unit tests.
* Prevent import `timm` if the `TIMMBackbone` is not used.
* Fix Windows CI.
* Move `init_model` to `mmcls.apis.hub`, and support pass nn.Module to all
model components.
* Fix requirements
* Rename `hub.py` to `model.py` and add unit tests.