Wifi managers improvements (#503)

* Add parameters to wifi manager: gateway name and base topic
Enable to restart the ESP and erase the parameters by MQTT

main/config_INA226.h

@@ -30,7 +30,7 @@ extern void setupINA226();
 extern void INA226toMQTT();
 /*----------------------------USER PARAMETERS-----------------------------*/
 /*-------------DEFINE YOUR MQTT PARAMETERS BELOW----------------*/
-#define subjectINA226toMQTT  Base_Topic Gateway_Name "/INA226toMQTT"
+#define subjectINA226toMQTT  "/INA226toMQTT"
 #define TimeBetweenReadingINA226 30000 // time between 2 INA226 readings
 
 #endif