New feature: handle stream as parameter

[arthur-fontaine]

To complete the realtime capability, we should be able to receive streams.

[arthur-fontaine]

https://github.com/arthur-fontaine/agrume/pull/94#issuecomment-2323103074

Neither XHR nor Fetch API allows to achieve a full-duplex communication. Fetch API simply does not allow duplex: "full" in the majority of runtimes (only Deno does), while XHR does not allow to send ReadableStream as body.

We need to either:

• [ ] ~Add WebSocket support (only if the body is a stream)~
• [x] Create ${routePath}/__agrume_write route that will allow to send body as stream with Fetch API, while streaming response of ${routePath}. If we do that, how do we match requests together? With a header provided by the client that provide a "request ID"? x-agrume-rid? It should necessary be a "complex" id (crypto.randomUUID()?)