This diff makes the implementation of the engine package more abstract by changing HTTPClient() to return a model.HTTPClient as opposed to returning an *http.Client. Part of https://github.com/ooni/probe/issues/2184
This diff makes the implementation of the engine package more abstract by changing HTTPClient() to return a model.HTTPClient as opposed to returning an *http.Client. Part of https://github.com/ooni/probe/issues/2184