Validate multi samples fixes #499

[ketan96-m]

Resolves #499

Added a validation step that raises an exception if duplicate samples are submitted.
Used the dataset, query and codegen to create the hash of the sample.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.90%. Comparing base (959c3af) to head (f7b1932).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #501      +/-   ##
==========================================
+ Coverage   83.64%   83.90%   +0.26%     
==========================================
  Files          26       26              
  Lines        1461     1485      +24     
==========================================
+ Hits         1222     1246      +24     
  Misses        239      239              

Flag	Coverage Δ
unittests	83.90% <100.00%> (+0.26%)	⬆️

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[ponyisi]

Thanks for all the work, @ketan96-m !