[Backport 2.x] Added Score Normalization and Combination feature

[martin-gaievski]

Backport PRs related to Hybrid Search feature:

Main PR with porting from feature branch:
61e6e98 from #241

Fix feature flag apporach:
5819df6 from #246

2a9f70a from #247

[martin-gaievski]

Currently failing due to errors in ml-commons, they do have PR in progress to fix that opensearch-project/ml-commons#1182

[codecov]

Codecov Report

Merging #242 (1ea4999) into 2.x (5228fc7) will decrease coverage by 3.27%.
Report is 5 commits behind head on 2.x.
The diff coverage is 84.11%.

@@             Coverage Diff              @@
##                2.x     #242      +/-   ##
============================================
- Coverage     89.55%   86.29%   -3.27%     
- Complexity      103      340     +237     
============================================
  Files             7       29      +22     
  Lines           316      992     +676     
  Branches         52      153     +101     
============================================
+ Hits            283      856     +573     
- Misses           16       70      +54     
- Partials         17       66      +49     

Files Changed	Coverage Δ
...nsearch/neuralsearch/query/NeuralQueryBuilder.java	89.01% <ø> (+1.09%)	⬆️
...nsearch/neuralsearch/query/HybridQueryBuilder.java	72.64% <72.64%> (ø)
...lsearch/search/query/HybridQueryPhaseSearcher.java	73.58% <73.58%> (ø)
...ensearch/neuralsearch/query/HybridQueryWeight.java	76.00% <76.00%> (ø)
...euralsearch/search/HybridTopScoreDocCollector.java	79.62% <79.62%> (ø)
...earch/processor/normalization/ScoreNormalizer.java	80.00% <80.00%> (ø)
...ensearch/neuralsearch/query/HybridQueryScorer.java	81.25% <81.25%> (ø)
...r/normalization/L2ScoreNormalizationTechnique.java	83.33% <83.33%> (ø)
...neuralsearch/processor/NormalizationProcessor.java	83.87% <83.87%> (ø)
...rmalization/MinMaxScoreNormalizationTechnique.java	84.61% <84.61%> (ø)
... and 15 more

[martin-gaievski]

Closing this one as I messed up with 2.x branch in fork before this merge. Work in done under #263