[FEATURE] Add abstraction to Async API for using Spark

[normanj-bitquill]

Currently the async API is designed to use the AWS EMR service when it needs Spark to process a query. For example, the EMRServerlessClientFactory class is used for getting an instance of AWSEMRServerless.

https://github.com/opensearch-project/sql/blob/main/async-query/src/main/java/org/opensearch/sql/spark/transport/config/AsyncExecutorServiceModule.java#L250

https://github.com/opensearch-project/sql/blob/main/async-query-core/src/main/java/org/opensearch/sql/spark/client/EMRServerlessClientFactoryImpl.java#L62

There should be an abstraction here so that async API uses an abstract service to start and manage Spark jobs. EMR would be an implementation of this abstract service. Another possible implementation is to use Docker.

Is your feature request related to a problem?
No

What solution would you like?
An abstract service for managing Spark jobs, along with an EMR implementation of this service.

What alternatives have you considered?
None, open to discussion.

Do you have any additional context?
In this OpenSearch Spark PR, the aws-java-sdk-emrserverless Jar file is updated to replace the AWSEMRServerless implementation. There should be a cleaner way of replacing usage of the EMR service.

[penghuo]

@normanj-bitquill in case opensearch-project/opensearch-spark#1003 is merged, do we still need this interface. In my understanding, it is only for test purpose?