Add sample for WASM (cdylib target type)

[calebcartwright]

Any basic wasm project will do, see for more info swellaby/vscode-rust-test-adapter#34 (comment)

More info:
https://developer.mozilla.org/en-US/docs/WebAssembly/Rust_to_wasm
https://developer.mozilla.org/en-US/docs/WebAssembly/Rust_to_wasm#Compiling_our_code_to_WebAssembly