[Backport 2.x] Star Tree Implementation [OnHeap]

[opensearch-trigger-bot]

Backport a2cef8f from #14512.

[github-actions]

❕ Gradle check result for 16f947a: UNSTABLE

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

Attention: Patch coverage is 74.02344% with 133 lines in your changes missing coverage. Please review.

Project coverage is 71.62%. Comparing base (fcd88aa) to head (16f947a).
Report is 2 commits behind head on 2.x.

Files	Patch %	Lines
...datacube/startree/builder/BaseStarTreeBuilder.java	70.41%	65 Missing and 6 partials ⚠️
...ex/datacube/startree/builder/StarTreesBuilder.java	68.57%	9 Missing and 2 partials ⚠️
...ube/startree/aggregators/MetricAggregatorInfo.java	74.07%	5 Missing and 2 partials ⚠️
...ors/numerictype/StarTreeNumericTypeConverters.java	36.36%	7 Missing ⚠️
...be/startree/utils/SequentialDocValuesIterator.java	65.00%	7 Missing ⚠️
...acube/startree/aggregators/SumValueAggregator.java	83.33%	4 Missing and 2 partials ⚠️
...e/aggregators/numerictype/StarTreeNumericType.java	75.00%	5 Missing and 1 partial ⚠️
...e/startree/aggregators/ValueAggregatorFactory.java	37.50%	3 Missing and 2 partials ⚠️
...tacube/startree/builder/OnHeapStarTreeBuilder.java	92.06%	5 Missing ⚠️
...tree/builder/StarTreeDocValuesIteratorAdapter.java	77.27%	2 Missing and 3 partials ⚠️
... and 2 more

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x   #15379      +/-   ##
============================================
+ Coverage     71.54%   71.62%   +0.08%     
- Complexity    63124    63247     +123     
============================================
  Files          5178     5197      +19     
  Lines        296088   296686     +598     
  Branches      43114    43177      +63     
============================================
+ Hits         211828   212515     +687     
+ Misses        66541    66329     -212     
- Partials      17719    17842     +123     

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