Fix unstable parallel tests (#202)

* update interface tests and configuration messages

* little debug

* little debug on both errors

* print all devs

* list of devices

* debug func

* handle interface close

* debug socks

* debug socks

* if ports match

* use random assigned ports

* remove unused const

* close management client connection when stopping engine

* GracefulStop when management clients are closed

* enable workflows on PRs too

* remove iface_test debug code

client/internal/engine.go

@@ -96,7 +96,13 @@ func (e *Engine) Stop() error {
 	e.syncMsgMux.Lock()
 	defer e.syncMsgMux.Unlock()
 
-	err := e.removeAllPeers()
+	err := e.mgmClient.Close()
+	if err != nil {
+		log.Errorf("failed closing engine's management client: %v", err)
+		return err
+	}
+
+	err = e.removeAllPeers()
 	if err != nil {
 		return err
 	}