[Backport 2.x] Refactor SSL Configuration (#4671)

[willyborankin]

Manual backport db6e7dc from #4671

[codecov]

Codecov Report

Attention: Patch coverage is 72.96588% with 206 lines in your changes missing coverage. Please review.

Project coverage is 63.81%. Comparing base (bb64636) to head (9827dab).
Report is 3 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
...rg/opensearch/security/ssl/SslSettingsManager.java	74.00%	12 Missing and 27 partials ⚠️
.../opensearch/security/ssl/config/KeyStoreUtils.java	56.32%	30 Missing and 8 partials ⚠️
...rg/opensearch/security/ssl/config/Certificate.java	59.72%	14 Missing and 15 partials ⚠️
...rch/security/ssl/config/KeyStoreConfiguration.java	64.78%	21 Missing and 4 partials ⚠️
...h/security/ssl/config/TrustStoreConfiguration.java	63.15%	16 Missing and 5 partials ⚠️
.../opensearch/security/ssl/config/SslParameters.java	72.05%	13 Missing and 6 partials ⚠️
.../api/ssl/TransportCertificatesInfoNodesAction.java	7.69%	12 Missing ⚠️
.../org/opensearch/security/ssl/SslConfiguration.java	76.08%	8 Missing and 3 partials ⚠️
...rch/security/ssl/config/SslCertificatesLoader.java	88.67%	3 Missing and 3 partials ⚠️
...urity/dlic/rest/api/SecuritySSLCertsApiAction.java	92.59%	0 Missing and 2 partials ⚠️
... and 3 more

Additional details and impacted files

@@            Coverage Diff             @@
##              2.x    #4837      +/-   ##
==========================================
- Coverage   64.61%   63.81%   -0.80%     
==========================================
  Files         320      330      +10     
  Lines       22384    23090     +706     
  Branches     3616     3741     +125     
==========================================
+ Hits        14463    14736     +273     
- Misses       6137     6521     +384     
- Partials     1784     1833      +49     

Files with missing lines	Coverage Δ
.../opensearch/security/OpenSearchSecurityPlugin.java	85.00% <100.00%> (+0.11%)	⬆️
...security/dlic/rest/api/SecurityRestApiActions.java	80.00% <ø> (ø)
.../security/ssl/OpenSearchSecureSettingsFactory.java	81.25% <100.00%> (ø)
...arch/security/ssl/OpenSearchSecuritySSLPlugin.java	87.02% <100.00%> (+0.72%)	⬆️
...org/opensearch/security/ssl/SecureSSLSettings.java	100.00% <ø> (ø)
...a/org/opensearch/security/ssl/config/CertType.java	100.00% <100.00%> (ø)
...org/opensearch/security/ssl/SslContextHandler.java	98.59% <98.59%> (ø)
...ensearch/security/ssl/util/SSLConfigConstants.java	79.16% <90.00%> (+1.38%)	⬆️
...urity/dlic/rest/api/SecuritySSLCertsApiAction.java	78.37% <92.59%> (+5.91%)	⬆️
...earch/security/ssl/rest/SecuritySSLInfoAction.java	79.10% <90.00%> (+3.63%)	⬆️
... and 9 more

... and 8 files with indirect coverage changes

[opensearch-trigger-bot]

The backport to 2.18 failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/security/backport-2.18 2.18
# Navigate to the new working tree
pushd ../.worktrees/security/backport-2.18
# Create a new branch
git switch --create backport/backport-4837-to-2.18
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 efbb404e31008974bce0ceb4af39852ab7c38bdd
# Push it to GitHub
git push --set-upstream origin backport/backport-4837-to-2.18
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/security/backport-2.18

Then, create a pull request where the base branch is 2.18 and the compare/head branch is backport/backport-4837-to-2.18.