Onboard segmentation inputs to new object

[ethanwharris]

What does this PR do?

Fixes #961

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[codecov]

Codecov Report

Merging #1015 (6a8972e) into master (e363aa8) will increase coverage by 2.07%.
The diff coverage is 92.37%.

@@            Coverage Diff             @@
##           master    #1015      +/-   ##
==========================================
+ Coverage   82.11%   84.18%   +2.07%     
==========================================
  Files         254      254              
  Lines       13590    13591       +1     
==========================================
+ Hits        11159    11442     +283     
+ Misses       2431     2149     -282     

Flag	Coverage Δ
unittests	84.18% <92.37%> (+2.07%)	⬆️

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

Impacted Files	Coverage Δ
flash/image/classification/data.py	95.62% <ø> (+13.66%)	⬆️
flash/image/data.py	93.33% <60.00%> (+18.68%)	⬆️
flash/image/segmentation/data.py	91.91% <93.00%> (+11.33%)	⬆️
flash/core/data/data_module.py	93.28% <100.00%> (+0.37%)	⬆️
flash/core/data/utilities/paths.py	91.52% <100.00%> (+7.88%)	⬆️
flash/image/segmentation/model.py	91.89% <100.00%> (+16.21%)	⬆️
flash/image/segmentation/output.py	76.81% <100.00%> (+7.69%)	⬆️
flash/text/question_answering/model.py	28.27% <0.00%> (-62.76%)	⬇️
flash/text/question_answering/data.py	28.16% <0.00%> (-58.87%)	⬇️
flash/text/classification/cli.py	53.84% <0.00%> (-46.16%)	⬇️
... and 58 more

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[tchaton]

LGTM !