[RN8209] Publish on change detect and heap usage optim (#1630)

Publish the RN8209 depending on a threshold added to a frequency
Also merge the 2 tasks into one to save heap

main/config_RN8209.h

@@ -44,6 +44,15 @@ extern void RN8209toMQTT();
 #endif
 
 #ifndef TimeBetweenReadingRN8209
-#  define TimeBetweenReadingRN8209 10000 // time between 2 RN8209 readings in ms
+#  define TimeBetweenReadingRN8209 500 // time between 2 RN8209 readings in ms
+#endif
+#ifndef TimeBetweenPublishingRN8209
+#  define TimeBetweenPublishingRN8209 10000 // time between 2 RN8209 publishing in ms
+#endif
+#ifndef PreviousPowerThreshold
+#  define PreviousPowerThreshold 0.1 // (percentage) threshold of the previous power that will trigger the publishing of the power value
+#endif
+#ifndef MinPowerThreshold
+#  define MinPowerThreshold 1 // (watt) Minimum power threshold that will trigger the publishing of the power value combined with PreviousPowerThreshold
 #endif
 #endif