:fire: Remove hardcoded keepalive - fix #301 (#314)
:fire: Remove hardcoded keepalive - fix #301 (#314)

Remove hardcoded KeepAlive for MQTT connection.
Default value of 15sec is already present in AsyncMQTT library
marvinroger/homie-esp8266,euphi/homie-esp8266,euphi/homie-esp8266,marvinroger/homie-esp8266,euphi/homie-esp8266,marvinroger/homie-esp8266,marvinroger/homie-esp8266,euphi/homie-esp8266