Fix opensearch.yml configMap Read-only file system error

[prudhvigodithi]

Description

Coming from an open PR #504, that removes opensearch.yml due to configMap Read-only file system error (as starting 2.12.0 OpenSearch security plugin need RW access to opensearch.yml when passed OPENSEARCH_INITIAL_ADMIN_PASSWORD, for more details ref: opensearch-project/security#3624).

This PR will have a fix to continue use the .Values.config and declare the opensearch.yml and does not throw configMap Read-only file system error.

With this the user can either use the default opensearch.yml or pass the opensearch.yml via .Values.config.

Issues Resolved

#224
part of: opensearch-project/security#3624, opensearch-project/security#3711

Check List

• Commits are signed per the DCO using --signoff

For any changes to files within Helm chart directories:

• Helm chart version bumped
• Helm chart CHANGELOG.md updated to reflect change

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[derek-ho]

Not familiar with this, but pulled locally and it works, so approving this as alternative if that's the better direction.

[prudhvigodithi]

Adding @TheAlgo @smlx @peterzhuamazon , to please have a look.

[DarshitChanpura]

Tested locally with @derek-ho along with admin credentials change (#503). It seems to be working locally. Approving this.

[prudhvigodithi]

Thanks @derek-ho and @DarshitChanpura.