Integrate explainability for hybrid query into RRF processor

[martin-gaievski]

Description

Adding explainability support into RRF processor. PR is for feature branch while application security review for RRF feature is in progress. PR for explainability feature #1014

Check List

• New functionality includes testing.
• [ ] New functionality has been documented.
• [ ] API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• [ ] Public documentation issue/PR created.

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[codecov]

Codecov Report

Attention: Patch coverage is 62.50000% with 12 lines in your changes missing coverage. Please review.

Project coverage is 78.53%. Comparing base (627fcb4) to head (8632f9c).

Files with missing lines	Patch %	Lines
...essor/normalization/RRFNormalizationTechnique.java	63.63%	7 Missing and 1 partial ⚠️
...processor/AbstractScoreHybridizationProcessor.java	60.00%	2 Missing ⚠️
...pensearch/neuralsearch/processor/RRFProcessor.java	75.00%	0 Missing and 1 partial ⚠️
...ssor/combination/RRFScoreCombinationTechnique.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@                           Coverage Diff                            @@
##             feature/rrf-score-normalization-v2    #1037      +/-   ##
========================================================================
+ Coverage                                 78.49%   78.53%   +0.03%     
- Complexity                                 1070     1075       +5     
========================================================================
  Files                                        90       91       +1     
  Lines                                      3729     3745      +16     
  Branches                                    619      619              
========================================================================
+ Hits                                       2927     2941      +14     
- Misses                                      541      543       +2     
  Partials                                    261      261              

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