Update index operations

[rohanshah18]

Problem

After adding open api generated code for control plane, there's a need for a wrapper for the index operations.

Solution

This PR adds a wrapper for index operations and associated integration tests. Couple of the integration tests are currently commented out and will be handled in the upcoming PR's.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Infrastructure change (CI configs, etc)
• Non-code change (docs, etc)
• None of the above: (explain here)

Test Plan

Ran integration tests.

[rohanshah18]

@austin-denoble Overall, this change will unblock you with adding collections and more refactoring are possible in future as we discussed internally. But any of the classes you're dealing with, are finalized as a part of this PR.

[austin-denoble]

Nice job, overall this looks good to me as a first step towards refactoring everything around the generated code, I think will unblock us to continue with the integration tests and then data plane refactoring.

Main concerns for me right now are making sure we make the UX reasonable for users. I think there's a bunch we could do to refactor PineconeClient, PineconeClientConfig, PineconeConnection, and PineconeConnectionConfig into something more reasonable, because it feels like a lot to keep track of right now.

In the other clients, we have a top-level Pinecone class that allows you to perform control plane operations, and then that class abstracts a lot of the internals for hitting the dataplane, so users can more easily target and work with indexes without a bunch of setup. I think we should try and shoot for something similar in Java, does that make sense? We can discuss further offline.