request: Support multiple package in a single WIT

[Mossaka]

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.

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:[email protected] {
             |                       ^
(base) ➜  hello-component-wasi-http-part2