remove duplicate code in main\ZgatewayBT.ino (#557)

* merge duplicate code into function setWorBMac

* rename setWorBMac to updateWorB

* add helper getDeviceByMac

* change updateWorB to use helper getDeviceByMac

* change isWhite to use helper getDeviceByMac

* change isBlack to use helper getDeviceByMac

* change isDiscovered to use helper getDeviceByMac

* eliminate duplicate devices walk for isWhite, isBlack and isDiscovered check

* fix a data corruption race between MQTTtoBT and discovery-functions

the ***Discovery functions every time create a new device unless this device is set to white-list before. as a result of this, the devices list contains the same mac multiple times with different flags

* eliminate duplicate devices walk for oneWhite check

because now we have a utility function 'createOrUpdateDevice' we can globally cache this as a single flag

* secure createOrUpdateDevice agains data races on multicore esp32

* fix the concept of the createOrUpdateDevice

c / c++ does not allow NULL as function parameter like modern languages

* use nkolban Semaphore helper class (already included and used from eos1d3/ESP32_BLE librarie)

this makes the semaphore handling more cleaner and readable

* merge duplicate code during createDiscovery into new helper createDiscoveryFromList

* replace excessive use of ZmqttDiscovery precompiler directive in ble advertised callbacks with dummy functions

for a better readability we can remove this because isDiscovered does not do a devices walk anymore

* fix build errors found by travis-ci

main/config_mqttDiscovery.h

@@ -29,6 +29,7 @@
 
 extern String getUniqueId(String name, String sufix);
 extern void pubMqttDiscovery();
+extern void createDiscoveryFromList(char *mac, char *sensorList[][8], int sensorCount);
 extern void createDiscovery(char * sensor_type,
                     char * state_topic, char * s_name, char * unique_id,
                     char * availability_topic, char * device_class, char * value_template,