[Backport 2.x] ImmutableOpenMap to j.u.Map

[Hailong-am]

Backport 9fbc083 from #830

Backport 990db5b from #825

Backport 354d20c from #771

Description of changes:

[Refactor] Metadata members from ImmutableOpenMap to j.u.Map was backported to 2.x
opensearch-project/OpenSearch#8241

cherry pick changes from #771

CheckList:

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[Hailong-am]

include #836 and #834 in this PR also

[codecov]

Codecov Report

Merging #838 (5979df0) into 2.x (c48129e) will increase coverage by 0.03%.
The diff coverage is 40.74%.

@@             Coverage Diff              @@
##                2.x     #838      +/-   ##
============================================
+ Coverage     75.92%   75.96%   +0.03%     
- Complexity     2900     2903       +3     
============================================
  Files           366      366              
  Lines         16554    16556       +2     
  Branches       2387     2395       +8     
============================================
+ Hits          12569    12576       +7     
+ Misses         2603     2600       -3     
+ Partials       1382     1380       -2     

Impacted Files	Coverage Δ
...atemanagement/step/shrink/AttemptMoveShardsStep.kt	57.70% <0.00%> (-0.70%)	⬇️
...atemanagement/step/shrink/WaitForMoveShardsStep.kt	45.45% <0.00%> (-5.32%)	⬇️
...exstatemanagement/step/shrink/WaitForShrinkStep.kt	40.00% <0.00%> (-2.00%)	⬇️
.../rollup/util/RollupFieldValueExpressionResolver.kt	61.53% <0.00%> (ø)
.../org/opensearch/indexmanagement/util/IndexUtils.kt	67.01% <0.00%> (-1.04%)	⬇️
...arch/indexmanagement/rollup/RollupMapperService.kt	58.58% <50.00%> (ø)
...management/indexstatemanagement/MetadataService.kt	63.70% <60.00%> (-0.48%)	⬇️
...ndexstatemanagement/IndexStateManagementHistory.kt	79.45% <66.66%> (+1.52%)	⬆️
...agement/indexstatemanagement/ManagedIndexRunner.kt	48.67% <100.00%> (+1.10%)	⬆️
...temanagement/opensearchapi/OpenSearchExtensions.kt	70.88% <100.00%> (-0.72%)	⬇️
... and 2 more

... and 8 files with indirect coverage changes

[Hailong-am]

docker security test failed due to docker image is not up to date.

docker image for 2.9.0 is created at "Created": "2023-06-21T02:19:02.649938963Z",

java.lang.NoSuchMethodError: 'java.util.Map org.opensearch.cluster.metadata.Metadata.getIndices()'
	at org.opensearch.indexmanagement.indexstatemanagement.DefaultIndexMetadataService.getMetadata(DefaultIndexMetadataService.kt:40) ~[opensearch-index-management-2.9.0.0-SNAPSHOT.jar:2.9.0.0-SNAPSHOT]

[Hailong-am]

@bowenlan-amzn can you help to review, as most this changes are from #771

[bowenlan-amzn]

Thank you!