[FEATURE] Avoid vendor-specific awsv4 library as a dependency

[dblock]

Is your feature request related to a problem?

In #279 we have added a vendor-specific, aws4 library as a dependency. By design we avoid vendor-specific code to not advantage any one vendor one way or another.

What solution would you like?

A way to make that dependency optional or potentially splitting opensearch-js into opensearch-js and an addon called opensearch-aws-js.

[harshavamsi]

@dblock I can take a stab at this.

From my understanding, optionalDependencies exist in npm but don't work in this use case because we would need to somehow pull in the dependency if a user requests to use the signer. It merely allows us to check if the dependency is installed and proceed without if not.

We would just need to create a separate package that we can import if needed.

Essentially, const { AwsSigv4Signer } = require('@opensearch-project/opensearch/aws'); becomes const { AwsSigv4Signer } = require('@opensearch-project/opensearch-aws-js');. WDYT?

Also, I see from other client implementations that we have vendor specific code in every client with sigv4. Do we open a meta issue in OpenSearch Clients to fix all of them?

[dblock]

@harshavamsi Thanks

1. I like your plan. Would call the package opensearch-js-aws.
2. At least in https://github.com/opensearch-project/opensearch-java the dependencies are optional and you don't need to always drag them unless you want to do SigV4.
3. Please do open a meta issue and if you see a client that doesn't do this, let's fix!