opensearch keystore used for key/truststore passwords

[todvora]

Move key/truststore passwords to Opensearch keystore, instead of putting them into the opensearch.yml config file.

Motivation and Context

Fixes #20926

How Has This Been Tested?

Existing integration tests

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (non-breaking change)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[moesterheld]

LGTM. Thank you.
I added a minimal change that uses the -x option for adding OS keystore secrets to avoid problems by bypassing the terminal prompt.