Fix wrong base topic if gateway_name is changed (#1242)

* Rectify and match parameters sizes.
Increase mqtt_topic_max_size from 100/50 to 150/75 bytes

* Faster and safer compare in cmpToMainTopic()

main/User_config.h

@@ -144,7 +144,7 @@ const byte mac[] = {0xDE, 0xED, 0xBA, 0xFE, 0x54, 0x95}; //W5100 ethernet shield
 //MQTT Parameters definition
 #if defined(ESP8266) || defined(ESP32) || defined(__AVR_ATmega2560__) || defined(__AVR_ATmega1280__)
 #  define parameters_size     60
-#  define mqtt_topic_max_size 100
+#  define mqtt_topic_max_size 150
 #  ifndef mqtt_max_packet_size
 #    ifdef MQTT_HTTPS_FW_UPDATE
 #      define mqtt_max_packet_size 2560
@@ -154,7 +154,7 @@ const byte mac[] = {0xDE, 0xED, 0xBA, 0xFE, 0x54, 0x95}; //W5100 ethernet shield
 #  endif
 #else
 #  define parameters_size      30
-#  define mqtt_topic_max_size  50
+#  define mqtt_topic_max_size  75
 #  define mqtt_max_packet_size 128
 #endif