feat(datastructures): add SelfOrganizingLinkedList implementation and tests

[iamcodinghere22]

This PR implements the Self-Organizing Linked List data structure using the "Move To Front(MTF)" heuristic.
In this implementation, whenever an element is accessed/searched, it is dynamically moved to the head of the list. This optimizes access time for frequently requested items by keeping them near the front, achieving an {O(1)} best-case lookup time for repeated accesses.

Changes Included

• Added SelfOrganizingLinkedList.java under com.thealgorithms.datastructures.lists.
• Added comprehensive unit test coverage in SelfOrganizingLinkedListTest.java verifying search, insertion, edge cases (empty list, non-existent elements), and move-to-front behavior.

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Testing

• All unit tests in SelfOrganizingLinkedListTest.java pass locally (mvn test -Dtest=SelfOrganizingLinkedListTest).
• Verified full build and test suite run successfully with JaCoCo code coverage.

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Checklist

• Code follows project coding guidelines.
• Unit tests have been added for new functionality.
• No duplicate code or classes introduced.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.74468% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.44%. Comparing base (31caee6) to head (259db0d).
⚠️ Report is 46 commits behind head on master.

Files with missing lines	Patch %	Lines
...datastructures/lists/SelfOrganizingLinkedList.java	94.28%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7575      +/-   ##
============================================
+ Coverage     79.89%   80.44%   +0.55%     
- Complexity     7348     7473     +125     
============================================
  Files           810      816       +6     
  Lines         23867    24092     +225     
  Branches       4703     4739      +36     
============================================
+ Hits          19069    19382     +313     
+ Misses         4036     3947      -89     
- Partials        762      763       +1     

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