Implement cosine similarity and cosinepair

[Mec-iS]

• Implement new distance cosine similarity
• Implement a variant of fastpair that uses cosine similarity

Checklist

• My branch is up-to-date with development branch.
• Everything works and tested on latest stable Rust.
• Coverage and Linting have been applied

Current behaviour

New expected behaviour

Change logs

• cosine distance
• fastpair with cosine distance CosinePair

[codecov]

Codecov Report

❌ Patch coverage is 46.54088% with 85 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.72%. Comparing base (9fef05e) to head (a438f64).
⚠️ Report is 2 commits behind head on development.

Files with missing lines	Patch %	Lines
src/algorithm/neighbour/cosinepair.rs	47.61%	66 Missing ⚠️
src/metrics/distance/cosine.rs	37.50%	15 Missing ⚠️
src/tree/decision_tree_classifier.rs	50.00%	4 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           development     #327      +/-   ##
===============================================
+ Coverage        45.23%   45.72%   +0.49%     
===============================================
  Files               90       93       +3     
  Lines             7775     7960     +185     
===============================================
+ Hits              3517     3640     +123     
- Misses            4258     4320      +62     

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