Publish refactoring (#298)

* factoring of the publishing function
* integration of json publishing to MQTT
* receiving and transcode json messages from mqtt
* replace the TRACE runtime condition by a buildtime one so as to decrease program size
* remove retainFlag parameter not necessary for the moment
* Increase the scope of tests for arduino mega and esp32
* Update arduinojson library to 5.13.3
* add macros to choose between simple or json publishing or both
* differentiate build test for ATmega2560
* correct wrong sprintf definition
* change IDE version for continuous integration
* let default warning level in arduino ide
* correct pins for ESP32
* reorganize user_config

config_BH1750.h

@@ -41,10 +41,7 @@
 
 /*----------------------------USER PARAMETERS-----------------------------*/
 /*-------------DEFINE YOUR MQTT PARAMETERS BELOW----------------*/
-#define LUX    Base_Topic Gateway_Name "/LIGHTtoMQTT/lux"
-#define FTCD   Base_Topic Gateway_Name "/LIGHTtoMQTT/ftcd"
-#define WATTSM2   Base_Topic Gateway_Name "/LIGHTtoMQTT/wattsm2"
-
+#define subjectBH1750toMQTT  Base_Topic Gateway_Name "/BH1750toMQTT"
 //Time used to wait for an interval before resending measured values
 unsigned long timebh1750 = 0;
 int BH1750_i2c_addr = 0x23; // Light Sensor I2C Address