Feature/centroid decomposition

[lens161]

• [ 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

Summary

This PR adds an implementation of Centroid Decomposition for trees. The algorithm recursively finds centroids of subtrees and builds a centroid tree of height O(log n). It is useful for distance queries and divide-and-conquer algorithms on trees.

Details

Allows adding edges to the original tree.

Builds the centroid decomposition with build().

Provides methods to get centroid parents and children.

Includes a method to visit all centroid ancestors of a node.

Includes JUnit tests.

CI check completed using: mvn clean verify

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.50000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.51%. Comparing base (5a68ba9) to head (e96043f).
⚠️ Report is 15 commits behind head on master.

Files with missing lines	Patch %	Lines
.../com/thealgorithms/tree/CentroidDecomposition.java	92.50%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7075      +/-   ##
============================================
+ Coverage     78.33%   78.51%   +0.17%     
- Complexity     6661     6776     +115     
============================================
  Files           752      759       +7     
  Lines         22180    22419     +239     
  Branches       4357     4397      +40     
============================================
+ Hits          17375    17602     +227     
- Misses         4106     4111       +5     
- Partials        699      706       +7     

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