In task T3302, stdout from conf_mode scripts called by vyos-configd was redirected to the console (or file, on boot) using the native Python contextmanager redirect_stdout. As understood, this contextmanager will only redirect stdout explicitly coming from the scripts themselves, and not that of any subbprocesses invoked --- however, capturing stdout from subprocesses is important, notably when debugging with, for example, vyos.ifconfig.debug. In this task, we provide a contextmanager to address this.