feat: Add Xs3Conversion algo with JUnit tests

[Tanmay-Singh3004]

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• [x] This pull request is all my own work -- I have not plagiarized it.
• [x] All filenames are in PascalCase.
• [x] All functions and variable names follow Java naming conventions.
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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 64.01%. Comparing base (6682c7c) to head (4897c67).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5743      +/-   ##
============================================
+ Coverage     63.96%   64.01%   +0.05%     
- Complexity     4172     4176       +4     
============================================
  Files           583      584       +1     
  Lines         16320    16338      +18     
  Branches       3150     3152       +2     
============================================
+ Hits          10439    10459      +20     
+ Misses         5456     5455       -1     
+ Partials        425      424       -1     

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[Tanmay-Singh3004]

@siriak , Thanks ! I first thought of adding this to the BcdConversion.java file, since the conversion to Excess-3 is almost similar to the Bcd conversion algorithm.