Integration-test Arti in a chutney network

For reliability, it would be good to have a script that can integration-test an arti client on a chutney network. It would be cool to have a 'flood mode' that we can use to benchmark the code when it's under load too.

Chutney already generates an "arti.toml" file as part of its configuration process that can be used to tell an Arti instance how to use that chutney network.