feat: recursion subsets added

[Tuhinm2002]

• [x] I have read CONTRIBUTING.md.
• [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.
• [x] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [x] All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 52.59%. Comparing base (e493eb2) to head (0d202a6). Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...a/com/thealgorithms/Recursion/GenerateSubsets.java	83.33%	2 Missing :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5503      +/-   ##
============================================
- Coverage     52.59%   52.59%   -0.01%     
- Complexity     3285     3287       +2     
============================================
  Files           527      528       +1     
  Lines         15312    15324      +12     
  Branches       2913     2913              
============================================
+ Hits           8054     8060       +6     
- Misses         6928     6932       +4     
- Partials        330      332       +2     

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[Tuhinm2002]

Please remove main, make the function return result instead of changing its parameter, give descriptive names to function parameters, add more test cases, and fix PR checks (build and formatter)

Hey I made the necessary changes and passed all checks now you can merge it