dba861d262
1. we want optionally to log the body (we don't want to log the body when we're fetching psiphon secrets or tor targets) 2. we want body logging to _also_ happen on error since this is quite useful to debug possible errors when accessing the API This diff adds the above functionality, which were previously described in https://github.com/ooni/probe/issues/1951. This diff also adds comprehensive testing.