[Backport] [2.x] [FEATURE] Improve built-in secure transports support

[reta]

Backport of #4179 to 2.x

[codecov]

Codecov Report

Attention: Patch coverage is 86.27451% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 65.75%. Comparing base (e66e013) to head (a95a706).

Additional details and impacted files

@@            Coverage Diff             @@
##              2.x    #4187      +/-   ##
==========================================
- Coverage   65.79%   65.75%   -0.05%     
==========================================
  Files         296      295       -1     
  Lines       21082    21090       +8     
  Branches     3456     3460       +4     
==========================================
- Hits        13871    13867       -4     
- Misses       5482     5489       +7     
- Partials     1729     1734       +5     

Files	Coverage Δ
.../opensearch/security/OpenSearchSecurityPlugin.java	84.50% <100.00%> (-0.30%)	⬇️
...opensearch/security/filter/SecurityRestFilter.java	70.37% <100.00%> (ø)
...earch/security/http/NonSslHttpServerTransport.java	100.00% <ø> (ø)
.../ssl/http/netty/Netty4ConditionalDecompressor.java	100.00% <100.00%> (ø)
...sl/http/netty/Netty4HttpRequestHeaderVerifier.java	87.50% <100.00%> (+1.78%)	⬆️
...arch/security/ssl/OpenSearchSecuritySSLPlugin.java	86.30% <66.66%> (+0.05%)	⬆️
.../security/ssl/OpenSearchSecureSettingsFactory.java	79.31% <75.00%> (-20.69%)	⬇️

... and 2 files with indirect coverage changes