Add function documentation, enhance comments in TowerOfHanoi.java

[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

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 54.80%. Comparing base (ee6cd64) to head (903c69a).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5533      +/-   ##
============================================
+ Coverage     54.73%   54.80%   +0.06%     
- Complexity     3453     3456       +3     
============================================
  Files           538      538              
  Lines         15583    15577       -6     
  Branches       2961     2961              
============================================
+ Hits           8530     8537       +7     
+ Misses         6695     6683      -12     
+ Partials        358      357       -1     

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[Hardvan]

I have replaced the main method with JUnit tests.

[Hardvan]

The suggested changes for the class & function documentation improvement have been implemented.

[siriak]

@alxkm please review

[Hardvan]

Thanks!