`HOST=127.0.0.1` vs `HOST=localhost`

I found that when using `curl http://localhost:8080` it works, but when using `node-fetch` like the webid-provider-tests test suite does, you get a connection refused error.
Running
```sh
HOST=127.0.0.1 composer serve-dev
```
Fixes this! :/
I'll see if I can make node-fetch send the same Host header as curl, so we can stop having to do this.