support sensor name mapping

pkg/ambient/config/ws_map.go

@@ -0,0 +1,12 @@
+package config
+
+// If the weather-station has a mapping, returns the new
+// name for the sensor
+func (ws *WeatherStation) MapSensor(sensor string) string {
+	for name, replacement := range ws.SensorMappings {
+		if name == sensor && replacement != "" {
+			return replacement
+		}
+	}
+	return sensor
+}