[PROPOSAL]Deprecate PointInTime Endpoints for Improved Standardization across clients

[saimedhi]

What/Why

What are you proposing?

Deprecate the CreatePointInTime and DeletePointInTime endpoints, and introduce CreatePit, DeletePit, DeleteAllPits, and GetAllPits instead. Any calls made to the deprecated APIs will be redirected to the newly added endpoints.
spec for new endpoints is here.

What problems are you trying to solve?

The aim is to standardize endpoints across all clients and enable the client to be entirely generated from the specification.

What is the developer experience going to be?

This change will simplify the process for developers to generate endpoints from the specification. Additionally, the generated endpoints will have consistent structures across all language clients.

Are there breaking changes to the User Experience?

No, the deprecated endpoints will still function, but they will automatically redirect to the new endpoints.

What will it take to execute?

Execution will follow a process similar to the current implementation for deprecating the getAliases endpoint.
https://github.com/opensearch-project/opensearch-php/blob/main/src/OpenSearch/Namespaces/IndicesNamespace.php#L1241