request: Support multiple package in a single WIT

relevent upstream work:

https://github.com/bytecodealliance/wasm-tools/pull/1577
https://github.com/bytecodealliance/wit-bindgen/pull/978

It seems like the latest research of `cargo-component` does not support multi-packages in WITs.

```shell
Caused by:
0: failed to parse local target from directory `/Users/mossaka/Developer/mossaka/hello-component-wasi-http-part2/wit`
1: expected ';', found '{'
--> /Users/mossaka/Developer/mossaka/hello-component-wasi-http-part2/wit/wasi_http.wit:1:23
|
1 | package wasi:io@0.2.0 {
| ^
(base) ➜ hello-component-wasi-http-part2
```