[FEATURE] Ability to extend this stack

[gaiksaya]

Is your feature request related to a problem?

This project deploys 2 stacks today which are dependent on each other. If the user wants to deploy this stack as a part of another CDK code base, they should be able to. We do not have a mechanism or instructions on how to consume this set up.
One of the solution is to publish this code package to npmjs.org

What solution would you like?

Ability to extend this stack so that it can be embedded with another CDK set up if required. One of the use case is opensearch-project/opensearch-devops#129
Also all the variables passed today are passed as context variables, maybe it would be helpful to have them as properties similar to https://github.com/opensearch-project/opensearch-ci#construct-props

What alternatives have you considered?

Deploy this set up first and then run the new CDK set up separately

Do you have any additional context?

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

[gaiksaya]

Did some research on how to do this and also synced up with @prudhvigodithi (Thanks!).
Looks like OsClusterEntrypoint which is responsible for deploying network and infra stack cannot be extended as it is not an instance of Stack base class. Planning to move the required checks and data transformation to respective classes. I suppose the entrypoint won't be useful much after that. Let me know what you think @rishabh6788 .

[gaiksaya]

Related opensearch-project/opensearch-build#4330

[gaiksaya]

opensearch-cluster-cdk is published to npmjs.org now: https://www.npmjs.com/package/@opensearch-project/opensearch-cluster-cdk
Users can now use the package programmatically in their typescript cdk codebase to deploy the stacks.