Reintroduice WASM32 support

[Erik1000]

I looked into reintroducing wasm32 support in #275

The build works, the problem (as mentioned in the README) are the tests:

• even without default features and only the features supported on wasm, tokio pulls in mio which cannot build on wasm
• wiremock does not support wasm
• one test uses tokio::net which isnt supported