feat(ext/http): Rework Deno.serve using hyper 1.0-rc3 (#18619)

This is a rewrite of the `Deno.serve` API to live on top of hyper
1.0-rc3. The code should be more maintainable long-term, and avoids some
of the slower mpsc patterns that made the older code less efficient than
it could have been.

Missing features:

- `upgradeHttp` and `upgradeHttpRaw` (`upgradeWebSocket` is available,
however).
- Automatic compression is unavailable on responses.

ext/net/ops_unix.rs

@@ -32,8 +32,8 @@ pub fn into_string(s: std::ffi::OsString) -> Result<String, AnyError> {
   })
 }
 
-struct UnixListenerResource {
-  listener: AsyncRefCell<UnixListener>,
+pub(crate) struct UnixListenerResource {
+  pub listener: AsyncRefCell<UnixListener>,
   cancel: CancelHandle,
 }