feat: add new fetch bindings to the rust kit

[Angelmmiguel]

This PR is built on top of #168. We will need to merge and rebase this branch before

This PR exposes new bindings to make HTTP requests from a Rust kit. To define the Request and Response we use the default structs from the http crate. Regarding errors, we will expose the HttpRequestError enum as it provides a more specific set of errors.

I also included a new example for rust.

It refs #165

Pending

• Enables a request with a Vec<u8> body
• Update docs to point to a specific Wasm Workers Server version. If someones tries to build a Rust worker with the new bindings using the previous wws version, it won't work.