feat: Support hot-reloading for security configuration files

[siegfriedweber]

Description

Support hot-reloading for security configuration files

Settings managed by the operator are hot-reloaded when changed, i.e. without pod restarts.

Part of stackabletech/issues#837

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes): https://testing.stackable.tech/view/02%20Operator%20Tests%20(custom)/job/opensearch-operator-it-custom/27/
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker