Check if WASI deps can be now directly got from wa.dev by cargo-component

[vigoo]

If it works, we need to update the golem-examples and the docs

[vigoo]

Not working with cargo-component 0.7.0, recheck after update:

[package.metadata.component.registries]
wasi = "https://wasi.wa.dev"

[package.metadata.component.target]
path = "wit"

[package.metadata.component.target.dependencies]
"wasi:sockets" = { version = "0.2.0", registry = "wasi" }
"wasi:io" = { version = "0.2.0", registry = "wasi" }
"wasi:clocks" = { version = "0.2.0", registry = "wasi" }

[vigoo]

With the app manifest based compilation this does not matter anymore - even if we could fetch the WITs using cargo-component's dependency support it is not enough because we need them in other phases of the app build.