Runs a series of tests against a running instance of a URLFrontier service.
The service is expected to run locally on port 7071, but the hostname and port values can be overridden on the command line e.g.
mvn -Durlfrontier.host=127.0.0.1 -Durlfrontier.port=7071 -Dmaven.test.skip=false test
The test suite also serves as an example of how to communicate with the service using gRPC.