Allow using WASI APIs in the Python extension (#533)

* Allow using WASI APIs in the Python extension

This commit adds support to the Python extension to load the WASI
implementation when a WASI module is seen allowing Python to load
WebAssembly modules that use WASI. This is pretty primitive right now
because there's no way to configure the environment/args/preopens/etc,
but it's hoped to be at least a start!

* rustfmt

* Refactor checks for the wasi module name

* Move the check into `wasmtime-wasi` itself
* Make it conservative for now and match anything that says `wasi*`
* Leave a `FIXME` for improving this later on

* Enable missing feature of winapi for `winx`

crates/interface-types/Cargo.toml

@@ -18,6 +18,7 @@ wasmparser = { version = "0.39.2", default-features = false }
 wasm-webidl-bindings = "0.6"
 wasmtime-jit = { path = '../jit', default-features = false }
 wasmtime-runtime = { path = '../runtime', default-features = false }
+wasmtime-wasi = { path = '../wasi' }
 
 [badges]
 maintenance = { status = "actively-developed" }