…fixed first anyway

…nchronous-io

…un without the need for Tokio

Doesn't seem to be used anywhere, so it's removed...

Needed in some cases for customization of the root fs.

Remove code duplication by reusing code paths

Remove he webc_runner and webc_runner_rt_wasi features from the wasmer_wasix crate.

These features do not require any additional dependencies, and just add
complexity for no good reason.

There was historical motivation for these features, because the
wasmer::Engine did not support module compilation on all target
architectures in the past, but now it is no longer neccessary.

Add Runtime::load_module / Runtime::load_module_sync methods that are
responsible for loading (compiling + caching) Webassembly modules.

This allows implementers to customize module compilation and caching,
for example to prevent concurrent compilation of the same module.

… a bespoke one. The bespoke one is only needed for the Web Browser

…time

…er 5 minutes

…asmer into asynchronous-io-with-fs-fixes

…asmer into asynchronous-io-with-fs-fixes