[Feature Request]: Request Response IO for Python SDK

[riteshghorse]

What would you like to happen?

Implement a request response IO to interact with REST APIs/GRPC in beam pipeline. This should be in parity with the Java implementaion tracked by #28934

Issue Priority

Priority: 2 (default / most feature requests should be filed as P2)

Issue Components

• [X] Component: Python SDK
• [ ] Component: Java SDK
• [ ] Component: Go SDK
• [ ] Component: Typescript SDK
• [ ] Component: IO connector
• [ ] Component: Beam YAML
• [ ] Component: Beam examples
• [ ] Component: Beam playground
• [ ] Component: Beam katas
• [ ] Component: Website
• [ ] Component: Spark Runner
• [ ] Component: Flink Runner
• [ ] Component: Samza Runner
• [ ] Component: Twister2 Runner
• [ ] Component: Hazelcast Jet Runner
• [ ] Component: Google Cloud Dataflow Runner

[riteshghorse]

Progress Tracking:

• [x] Python bindings for Mock API to test the IO
• [x] Caller class interface
• [x] Cache PTransform (Read/Write)
• [x] Integration Test
• [ ] Example

[riteshghorse]

#30307 has the cache support and integration test