feat: Add `GangScheduling` new algorithm with Junit tests

[Hardvan]

• [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 95.23810% with 1 line in your changes missing coverage. Please review.

Project coverage is 69.86%. Comparing base (1d19449) to head (29168e2).

Files with missing lines	Patch %	Lines
...a/com/thealgorithms/scheduling/GangScheduling.java	95.23%	0 Missing and 1 partial :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5819      +/-   ##
============================================
+ Coverage     69.82%   69.86%   +0.04%     
- Complexity     4730     4735       +5     
============================================
  Files           632      633       +1     
  Lines         17274    17295      +21     
  Branches       3322     3324       +2     
============================================
+ Hits          12061    12083      +22     
+ Misses         4757     4756       -1     
  Partials        456      456              

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