[Enhance]: Use mmcv root model registry.

[RangiLyu]

Motivation

MMEditing did not use mmcv's MODELS registry as root/parent registry. This PR makes it impossible to build models across projects.

Modification

mmpose/models/registry.py

from mmcv.cnn import MODELS as MMCV_MODELS
from mmcv.utils import Registry

MODELS = Registry('model', parent=MMCV_MODELS)
BACKBONES = MODELS
COMPONENTS = MODELS
LOSSES = MODELS

MODELS = Registry(
    'models', build_func=build_model_from_cfg, parent=MMCV_MODELS)

[codecov]

Codecov Report

Merging #660 (2474414) into master (5170a64) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #660      +/-   ##
==========================================
+ Coverage   80.49%   80.51%   +0.01%     
==========================================
  Files         198      198              
  Lines       11233    11234       +1     
  Branches     1795     1795              
==========================================
+ Hits         9042     9045       +3     
+ Misses       1915     1914       -1     
+ Partials      276      275       -1     

Flag	Coverage Δ
unittests	80.48% <100.00%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmedit/__init__.py	50.00% <100.00%> (ø)
mmedit/models/registry.py	100.00% <100.00%> (ø)
...ls/components/stylegan2/generator_discriminator.py	86.14% <0.00%> (+1.20%)	⬆️

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[wangruohui]

This modification will merge all three registries into a single one, which follows standard of other repos do.