Add example wasm component and runner which embeds the component

README.md

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+# Wasmtime test
+
+Example project showcasing how to run a wasm component with wasmtime, and how to build the runnable component using cargo component.
+
+## Structure
+
+### component
+
+This package includes an example wasm component, which simply calls a `hello()` function provided by the runner.
+
+### runner
+
+This package includes an example runtime, to run the built wasm component from the component package.
+
+## Build
+
+First run `cargo component build -p component --release` to build the wasm component.
+
+Then run `cargo run -p runner --release` to run the runner with the build wasm component from the previous step.
+
+## Troubleshooting
+
+If you see errors about imports missing when trying to run the compiled component, it's likely there's a dependency on std that isn't supported by the runtime linker (e.g. by calling `println!()`).
+To build without std components, run the following:
+
+`cargo component build --target wasm32-unknown-unknown --release`
+
+Note this is only required when using std components. Preferably don't do this, and instead
+use #![no_std] to not accidentally use std. Otherwise, you'll need to either use a runtime that includes std (e.g. wasmtime cli), or add the appropriate imports to the runtime linker.
+
+To check the imports and exports for a compiled .wasm component, run the following (where component.wasm is the compiled .wasm file to inspect):
+
+`wasm-tools component wit component.wasm`