Adding efficient filtering

[martin-gaievski]

Description

Adding code from POC branch to a feature branch in main repo.
This implementation is not production ready, code isn't polished and mainly most of tests are missing expect for the very basic unit test.

In this change we:

• parsing out filter section from the knn query request and pass it to the query factory
• adding support for core query as a filter using core OpenSearch parser

Issues Resolved

#376

Check List

• New functionality includes testing.
  • All tests pass
• Commits are signed as per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Dexveloper Certificate of Origin and signing off your commits, please check here.

[codecov-commenter]

Codecov Report

Merging #515 (ecf8aee) into feature/efficient-filtering (507bafe) will increase coverage by 0.00%.
The diff coverage is 88.13%.

@@                      Coverage Diff                       @@
##             feature/efficient-filtering     #515   +/-   ##
==============================================================
  Coverage                          84.04%   84.05%           
- Complexity                          1019     1022    +3     
==============================================================
  Files                                146      146           
  Lines                               4188     4240   +52     
  Branches                             373      376    +3     
==============================================================
+ Hits                                3520     3564   +44     
- Misses                               492      500    +8     
  Partials                             176      176           

Impacted Files	Coverage Δ
...rg/opensearch/knn/index/query/KNNQueryBuilder.java	70.67% <77.27%> (-0.12%)	⬇️
...rg/opensearch/knn/index/query/KNNQueryFactory.java	92.30% <94.59%> (+6.59%)	⬆️
...java/org/opensearch/knn/index/query/KNNWeight.java	78.94% <0.00%> (ø)

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