feat: Add MedianFinder 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 80.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 70.34%. Comparing base (d572997) to head (656c19e).

Files with missing lines	Patch %	Lines
...ealgorithms/datastructures/heaps/MedianFinder.java	80.00%	1 Missing and 2 partials :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5837      +/-   ##
============================================
+ Coverage     70.32%   70.34%   +0.01%     
- Complexity     4772     4780       +8     
============================================
  Files           638      639       +1     
  Lines         17325    17340      +15     
  Branches       3335     3337       +2     
============================================
+ Hits          12183    12197      +14     
  Misses         4681     4681              
- Partials        461      462       +1     

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