fix: Fixed PyTorch tensor cropping and extended script support

[fg-mindee]

As per #428, this PR introduces the following modifications:

• added option to correctly crop images that are channels_first
• updated predictors accordingly
• added support of PyTorch in the evaluation script
• added support of PyTorch in the analysis script
• added CI job to check Pytorch evaluation
• added metric formatter when a metric is undefined
• fixed predictor call when some crops have a size of 0

Resolves #428

Any feedback is welcome!

[codecov]

Codecov Report

Merging #458 (c74093d) into main (3e7e9de) will decrease coverage by 0.06%.
The diff coverage is 84.21%.

@@            Coverage Diff             @@
##             main     #458      +/-   ##
==========================================
- Coverage   95.86%   95.79%   -0.07%     
==========================================
  Files          96       96              
  Lines        4013     4023      +10     
==========================================
+ Hits         3847     3854       +7     
- Misses        166      169       +3     

Flag	Coverage Δ
unittests	95.79% <84.21%> (-0.07%)	⬇️

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

Impacted Files	Coverage Δ
doctr/models/_utils.py	91.46% <71.42%> (-1.04%)	⬇️
doctr/models/core.py	93.84% <91.66%> (-0.42%)	⬇️
...dels/detection/differentiable_binarization/base.py	91.35% <0.00%> (-0.62%)	⬇️

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[charlesmindee]

Thanks!