[Feature] Add inferencer for lidar-based segmentation

[Xiangxu-0103]

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Motivation

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Modification

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Checklist

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[codecov]

Codecov Report

Patch coverage: 59.11% and project coverage change: +0.58 🎉

Comparison is base (d84e081) 46.37% compared to head (229272e) 46.95%.

❗ Current head 229272e differs from pull request most recent head 007a1db. Consider uploading reports for the commit 007a1db to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           dev-1.x    #2304      +/-   ##
===========================================
+ Coverage    46.37%   46.95%   +0.58%     
===========================================
  Files          259      265       +6     
  Lines        21390    22263     +873     
  Branches      3379     3497     +118     
===========================================
+ Hits          9919    10453     +534     
- Misses       10827    11141     +314     
- Partials       644      669      +25     

Flag	Coverage Δ
unittests	46.95% <59.11%> (+0.58%)	⬆️

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

Impacted Files	Coverage Δ
mmdet3d/datasets/s3dis_dataset.py	78.08% <ø> (ø)
mmdet3d/datasets/scannet_dataset.py	82.75% <ø> (ø)
mmdet3d/datasets/transforms/__init__.py	100.00% <ø> (ø)
mmdet3d/datasets/waymo_dataset.py	17.72% <ø> (ø)
mmdet3d/evaluation/__init__.py	100.00% <ø> (ø)
...tion/functional/waymo_utils/prediction_to_waymo.py	0.00% <0.00%> (ø)
mmdet3d/evaluation/metrics/seg_metric.py	62.50% <0.00%> (ø)
mmdet3d/evaluation/metrics/waymo_metric.py	8.11% <ø> (ø)
mmdet3d/models/dense_heads/centerpoint_head.py	21.77% <0.00%> (ø)
mmdet3d/models/dense_heads/fcaf3d_head.py	16.23% <ø> (ø)
... and 54 more

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