The `wasmtime` crate currently lives in `crates/api` for historical reasons, because we once called it `wasmtime-api` crate. This creates a stumbling block for new contributors. As discussed on Zulip, rename the directory to `crates/wasmtime`.
This is the wasmtime-wast crate, which contains an implementation of WebAssembly's
"wast" test scripting language, which is used in the
WebAssembly spec testsuite, using wasmtime for execution.