Add support for certificates hot reload

[willyborankin]

Description

Added support for certificates hot reload

Issues Resolved

#4427

Check List

• New functionality includes testing
• New functionality has been documented
• New Roles/Permissions have a corresponding security dashboards plugin PR
• API changes companion pull request created
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Attention: Patch coverage is 74.35897% with 10 lines in your changes missing coverage. Please review.

Project coverage is 71.42%. Comparing base (9b67d54) to head (b1f826c).

Files with missing lines	Patch %	Lines
...rg/opensearch/security/ssl/SslSettingsManager.java	79.31%	6 Missing ⚠️
.../opensearch/security/OpenSearchSecurityPlugin.java	33.33%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4880      +/-   ##
==========================================
- Coverage   71.45%   71.42%   -0.03%     
==========================================
  Files         334      334              
  Lines       22509    22543      +34     
  Branches     3582     3586       +4     
==========================================
+ Hits        16084    16102      +18     
- Misses       4633     4645      +12     
- Partials     1792     1796       +4     

Files with missing lines	Coverage Δ
...org/opensearch/security/ssl/SslContextHandler.java	98.87% <100.00%> (+0.03%)	⬆️
...g/opensearch/security/support/ConfigConstants.java	95.23% <ø> (ø)
.../opensearch/security/OpenSearchSecurityPlugin.java	83.56% <33.33%> (-0.45%)	⬇️
...rg/opensearch/security/ssl/SslSettingsManager.java	71.59% <79.31%> (-0.41%)	⬇️

... and 5 files with indirect coverage changes

[cwperks]

@willyborankin Can you open a documentation PR for this as well since this adds a new setting?