feat: allow overwrite opensearch home to 2.x

[shyim]

Manual cherry pick of #6956 to 2.x branch

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/13692/
• CommitID: 20b18b4

[codecov-commenter]

Codecov Report

Merging #7049 (e14fbe3) into 2.x (19e66c6) will increase coverage by 0.13%.
The diff coverage is 87.50%.

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@@             Coverage Diff              @@
##                2.x    #7049      +/-   ##
============================================
+ Coverage     70.31%   70.45%   +0.13%     
- Complexity    59539    59608      +69     
============================================
  Files          4824     4824              
  Lines        286330   286321       -9     
  Branches      41626    41624       -2     
============================================
+ Hits         201345   201734     +389     
+ Misses        68196    67714     -482     
- Partials      16789    16873      +84     

Impacted Files	Coverage Δ
.../main/java/org/opensearch/env/NodeEnvironment.java	77.92% <83.33%> (-1.24%)	⬇️
...search/index/store/remote/filecache/FileCache.java	70.96% <100.00%> (+0.47%)	⬆️
...index/store/remote/filecache/FileCacheCleaner.java	72.72% <100.00%> (-1.56%)	⬇️

... and 510 files with indirect coverage changes

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[peterzhuamazon]

Need this one to follow up to resolve an issue:

• Resolve windows opensearch-env.bat having variable delayed expansion issues on OPENSEARCH_HOME assignment introduced in #6956 #7080

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: UNSTABLE ❕
• TEST FAILURES:

      1 org.opensearch.backwards.MixedClusterClientYamlTestSuiteIT.test {p0=pit/10_basic/Delete all}

• URL: https://build.ci.opensearch.org/job/gradle-check/13886/
• CommitID: e14fbe3
  Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.