Added ADFGVXCipher.java

[bennybebo]

• 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 Uncyclopedia 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 92.59259% with 4 lines in your changes missing coverage. Please review.

Project coverage is 63.72%. Comparing base (8722598) to head (f13913a).

Files with missing lines	Patch %	Lines
...n/java/com/thealgorithms/ciphers/ADFGVXCipher.java	92.59%	1 Missing and 3 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5631      +/-   ##
============================================
+ Coverage     63.61%   63.72%   +0.11%     
- Complexity     4111     4130      +19     
============================================
  Files           577      578       +1     
  Lines         16143    16197      +54     
  Branches       3102     3117      +15     
============================================
+ Hits          10269    10322      +53     
  Misses         5452     5452              
- Partials        422      423       +1     

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[siriak]

The code looks good, could you please add some JUnit tests? (see https://github.com/TheAlgorithms/Java/tree/master/src/test/java/com/thealgorithms)

[siriak]

Looks good, thanks!