feat: Add IPv6Converter new algorithm with Junit tests

[Hardvan]

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 70.37037% with 8 lines in your changes missing coverage. Please review.

Project coverage is 70.16%. Comparing base (009c2b3) to head (19e1d0b).

Files with missing lines	Patch %	Lines
...a/com/thealgorithms/conversions/IPv6Converter.java	70.37%	4 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5783   +/-   ##
=========================================
  Coverage     70.16%   70.16%           
- Complexity     4754     4761    +7     
=========================================
  Files           634      635    +1     
  Lines         17295    17322   +27     
  Branches       3327     3333    +6     
=========================================
+ Hits          12135    12154   +19     
- Misses         4704     4708    +4     
- Partials        456      460    +4     

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[siriak]

Please fix PR checks

[Hardvan]

I have fixed the PR checks.