[FEATURE] Parse additionalConfig and additionalOsdConfig for existing key/values

[gaiksaya]

Is your feature request related to a problem?

The current implementation of additionalConfig and additionalOsdConfig, just blindly adds the config to the opensearch.yml and opensearch-Dashboards.yml respectively. If the user wants to override the current default config (Example: cluster.name), it is not possible

What solution would you like?

Parse the existing config key/value pairs in opensearch.yml and opensearch-Dashboards.yml with additionalConfig and additionalOsdConfig values, remove existing duplicate config and then add additional one.

What alternatives have you considered?

A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?

Add any other context or screenshots about the feature request here.