Make Request and RequestBuilder implement IntoFuture

[ultrabear]

This PR adds IntoFuture implementations (and Future implementing types RequestFuture and RequestBuilderFuture) for Request and RequestBuilder

This makes it possible to have smoother usage of the API, with patterns like Request::get("/foo").await now being possible (previously Request::get("/foo").send().await.

This is my first time handwriting Future's, so they are simple enum based state machines and or just wrap inner futures, I see no reasons they would be noticeably less performant than the previous implementation however.

I realize as I write that it may have been a better idea to make RequestFuture and RequestBuilderFuture public in an unreachable module (not reference-able by userspace or documented publicly), if that change is wanted or to simply make them doc(hidden), or to just leave it be and give them a sentence of docs explaining what they are, I'm willing to do any of the three in a followup commit within this PR

[ultrabear]

Some CI tests are failing because they try to grab wasm32-wasi, which has been removed. the target was renamed to wasm32-wasip1.

[ultrabear]

I do not know why the gloo-worker CI tests failed based on my PR, changes were only made in gloo-net and there does not appear to be a dependency chain where gloo-worker imports gloo-net

[ultrabear]

Closing as library appears unmaintained