Add mmseg2torchserve tool

[daavoo]

This P.R. enables serving MMSegmentation models with TorchServe. A new section Model Serving has been added in useful_tools.md.

[codecov]

Codecov Report

Merging #552 (7eee01e) into master (8558163) will decrease coverage by 1.61%.
The diff coverage is 74.64%.

❗ Current head 7eee01e differs from pull request most recent head 32907fd. Consider uploading reports for the commit 32907fd to get more accurate results

@@            Coverage Diff             @@
##           master     #552      +/-   ##
==========================================
- Coverage   86.76%   85.14%   -1.62%     
==========================================
  Files         101      105       +4     
  Lines        5250     5670     +420     
  Branches      849      923      +74     
==========================================
+ Hits         4555     4828     +273     
- Misses        535      663     +128     
- Partials      160      179      +19     

Flag	Coverage Δ
unittests	85.14% <74.64%> (-1.62%)	⬇️

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

Impacted Files	Coverage Δ
mmseg/datasets/pipelines/transforms.py	97.12% <ø> (ø)
mmseg/models/decode_heads/psp_head.py	100.00% <ø> (ø)
mmseg/models/segmentors/cascade_encoder_decoder.py	100.00% <ø> (ø)
mmseg/models/utils/inverted_residual.py	100.00% <ø> (ø)
mmseg/models/utils/ckpt_convert.py	4.28% <4.28%> (ø)
mmseg/datasets/ade.py	40.54% <24.13%> (-59.46%)	⬇️
mmseg/models/segmentors/encoder_decoder.py	88.35% <25.00%> (-2.50%)	⬇️
mmseg/models/backbones/hrnet.py	82.45% <52.94%> (-1.85%)	⬇️
mmseg/models/backbones/cgnet.py	94.63% <53.84%> (-2.13%)	⬇️
mmseg/models/backbones/unet.py	94.87% <53.84%> (-0.93%)	⬇️
... and 31 more

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[xvjiarui]

Hi @daavoo
Thanks for the nice PR! We will review it recently.

[Junjun2016]

Hi @daavoo
Sorry for the late reply.
@AllentDan will help with the review.

[AllentDan]

Hi, it worked all fine for me except the image. We may move 3dogs_mask.png to the folder resources here for better management.

[Junjun2016]

Hi @AllentDan
@daavoo has updated this PR.
Could you please review it again?

[Junjun2016]

Hi @daavoo
Could you please add some unittest?

[AllentDan]

Hi, @Junjun2016. For codes in tools other than mmseg, we may not consider unittests.

[Junjun2016]

Hi, @Junjun2016. For codes in tools other than mmseg, we may not consider unittests.

Got it.