Share stdio implementations in WASIp{2,3} (#11368)

* Share stdio implementations in WASIp{2,3}

This commit is a refactoring of the
`wasmtime_wasi::{cli,p2::stdio,p3::cli}` modules to share more co

Share stdio implementations in WASIp{2,3} (#11368)

* Share stdio implementations in WASIp{2,3}

This commit is a refactoring of the
`wasmtime_wasi::{cli,p2::stdio,p3::cli}` modules to share more code. The
generic trait object that represents stdio now has the ability to
acquire either a p2 stream or an async-based stream. The acquisition of
p2 has a default implementation so in the future this can be primarily
`Async{Read,Write}`-based.

Many trait implementations and types and such were all consolidated
together into the `wasmtime_wasi::cli` module. One-off implementations
in p2/p3 are now shared in one location and `WasiCtxBuilder` no longer
needs any generics for different stdio streams.

Functionally this necessitated the addition of `Async{Read,Write}`
implementations for some "base" implementations of stdio primitives.
Implementations were mostly trivial except for a few adapters which were
significantly more complicated, namely the `Async{Read,Write}Stream`
adapter which converts a single `Async{Read,Write}` into the stdio of a
component.

Finally the stdin implementation for p3 was refactored to avoid use of
`tokio::io::stdin()` which generally isn't safe to use. It's replaced
with a custom `AsyncRead` using the worker thread implementation we have
in the crate already.

Eventually I hope to remove the distinction between `p{2,3}::WasiCtx`
and have these be the same type. This will make it nicer to only have a
single `WasiView` trait and additionally make it easier to
simultaneously implement all of WASIp{1,2,3}.

* Fix build of C API

* Fix build of `wasmtime serve`

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