added Normalization transformation to per_sample transforms

[Nico995]

What does this PR do?

Adds the ability to normalize input data in SemanticSegmentationData module.

Fixes #1398

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[codecov]

Codecov Report

Merging #1399 (bb9b383) into master (04f1b8f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head bb9b383 differs from pull request most recent head 327fec9. Consider uploading reports for the commit 327fec9 to get more accurate results

@@           Coverage Diff           @@
##           master    #1399   +/-   ##
=======================================
  Coverage   92.92%   92.92%           
=======================================
  Files         286      286           
  Lines       12835    12837    +2     
=======================================
+ Hits        11927    11929    +2     
  Misses        908      908           

Flag	Coverage Δ
unittests	92.92% <100.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
flash/image/segmentation/input_transform.py	94.11% <100.00%> (+0.36%)	⬆️

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[ethanwharris]

Awesome!!! LGTM 😃