Proposal: Request Reply Resource

**Problem**
While eventing provides components for asynchronous workloads and event processing, it is sometimes useful to make synchronous calls. By providing a Request Response Proxy we can allow users to have this synchronous experience when they want to.

A (very early WIP) feature proposal doc is here: https://docs.google.com/document/d/1vrCfIH9wRrsl8j7XpHK5XiVRgnx5nB4mLHsp0AxU_0Y/edit?usp=sharing

**[Persona:](https://github.com/knative/eventing/blob/main/docs/personas.md)**
Which persona is this feature for?

**Exit Criteria**
A measurable (binary) test that would indicate that the problem has been resolved.

**Time Estimate (optional):**
How many developer-days do you think this may take to resolve? 10

**Additional context (optional)**
Add any other context about the feature request here.

A POC of how this proxy could work is here: https://github.com/Cali0707/knative-llm-tool-provider/blob/main/request-proxy/main.go