Add Base64Util with encode/decode methods and unit tests

[TonGonzalez]

• 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

Description

This PR introduces Base64Util, a utility class for Base64 encoding and decoding of strings.

Key points:

• Added encode(String input) and decode(String base64) methods.
• Implemented comprehensive unit tests in Base64UtilTest covering:
  • Normal strings
  • Empty strings
  • Null input
  • Invalid Base64 input
• Followed the coding and testing conventions of the TheAlgorithms/Java repository.
• Ensures safe and reliable Base64 conversion for various use cases.

If applicable, reference related issue: #<6585>

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.51%. Comparing base (d8ddb07) to head (ca86125).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6593      +/-   ##
============================================
+ Coverage     75.50%   75.51%   +0.01%     
- Complexity     5688     5692       +4     
============================================
  Files           694      695       +1     
  Lines         19570    19579       +9     
  Branches       3791     3791              
============================================
+ Hits          14776    14785       +9     
  Misses         4217     4217              
  Partials        577      577              

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[Arnav-NK]

did you solved the conflict i am getting the same can you help me with that please ?

[TonGonzalez]

Yes, I managed to solve it! I ended up using a website to do the formatting for me, I copied the code and pasted it into the website and then updated my code :) > did you solved the conflict i am getting the same can you help me with that please ?

[DenizAltunkapan]

Please format your code and fix the failing workflows so I can start the review. @TonGonzalez

[github-actions]

This pull request has been automatically closed because its workflows or checks failed and it has been inactive for more than 14 days. Please fix the workflows and reopen if you'd like to continue. Merging from main/master alone does not count as activity.