Re-publish discovery topics on re-connect (via cfg, disabled by default) (#1274)

Resolves https://github.com/1technophile/OpenMQTTGateway/issues/1273

Signed-off-by: Sami Salonen <ssalonen@gmail.com>

Signed-off-by: Sami Salonen <ssalonen@gmail.com>

main/config_mqttDiscovery.h

@@ -113,6 +113,11 @@ void announceDeviceTrigger(bool use_gateway_info,
                            char* device_mac);
 
 #define discovery_Topic "homeassistant"
+// discovery_republish_on_reconnect false to publish discovery topics over MQTT only with first connect
+// discovery_republish_on_reconnect true to always republish discovery topics over MQTT when connection is re-established
+#ifndef discovery_republish_on_reconnect
+#  define discovery_republish_on_reconnect false
+#endif
 
 #define DEVICEMANUFACTURER "OMG_community"