Heltec SSD1306 Display Support (#1283)

My environment

[env:heltec-display]   ; Heltec ESP32 Board with SSD1306 display
platform = ${com.esp32_platform}
board = heltec_wifi_lora_32_V2
build_type = debug
monitor_filters = esp32_exception_decoder
board_build.partitions = min_spiffs.csv
extra_scripts = pre:scripts/omg_firmware_version.py
lib_deps =
  ${com-esp.lib_deps}
  ${libraries.wifimanager32}
  ${libraries.heltec}
;  ${libraries.m5stickcp}

build_flags =
  ${com-esp.build_flags}
  ${test_env.build_flags}
; *** OpenMQTTGateway Config ***
  '-UZmqttDiscovery'          ; disables MQTT Discovery
  '-DvalueAsATopic=true'
  '-DLOG_LEVEL=LOG_LEVEL_TRACE'
; *** OpenMQTTGateway Modules ***
  '-DZboardHELTEC="HELTEC"'
; *** Heltec Board Options ***
  '-DDEBUG_OLEDDISPLAY(...)=Serial.printf( __VA_ARGS__ )'
  '-DLOG_TO_LCD=true'         ; Enable log to LCD
  '-DLED_ERROR=2'
  '-DONBOARD_LED=25'          ; Onboard LED is GPIO 25 on the Heltec Board

monitor_port = /dev/cu.SLAB_USBtoUART
monitor_speed = 921600
upload_port = /dev/cu.SLAB_USBtoUART
upload_speed = 921600

1 - Set default LCD log level to WARNING
2 - Implemented a macro based displayPrint function that will be usable across different displays

- Added logo display when idle
- Fixed log-lcd mqtt function
- Enable OLED Display on Heltec Boards

platformio.ini

@@ -137,6 +137,7 @@ rtl_433_ESP = https://github.com/NorthernMan54/rtl_433_ESP.git#v0.0.4
 emodbus =  miq19/eModbus@1.0.0
 gfSunInverter = https://github.com/BlackSmith/GFSunInverter.git#v1.0.1
 decoder = https://github.com/theengs/decoder.git#v0.9.0
+ssd1306 = thingpulse/ESP8266 and ESP32 OLED driver for SSD1306 displays@^4.3.0
 
 [env]
 framework = arduino
@@ -859,15 +860,20 @@ build_flags =
   # Reading battery level every minutes should be more than enought
   '-DTimeBetweenReadingADC=60000'
 
-[env:heltec-wifi-lora-32-868]
+[env:heltec-wifi-lora-32-868]  ; Heltec ESP32 Board with SSD1306 display
 platform = ${com.esp32_platform}
 board = heltec_wifi_lora_32
 lib_deps =
   ${com-esp.lib_deps}
   ${libraries.wifimanager32}
   ${libraries.lora}
+  ${libraries.ssd1306} 
 build_flags =
   ${com-esp.build_flags}
+    ; *** OpenMQTTGateway Modules ***
+  '-DZboardHELTEC="HELTEC"'
+  '-DLOG_TO_LCD=true'         ; Enable log to LCD
+  ;  '-DLOG_LEVEL_LCD=LOG_LEVEL_TRACE'    // default is notice log level
   '-DZgatewayLORA="LORA"'
   '-DLORA_BAND=868E6'
   '-DGateway_Name="OpenMQTTGateway_ESP32_LORA"'
@@ -875,15 +881,20 @@ build_flags =
   '-DTimeLedON=0.1'
   '-DLED_SEND_RECEIVE_ON=1'
 
-[env:heltec-wifi-lora-32-915]
+[env:heltec-wifi-lora-32-915]   ; Heltec ESP32 Board with SSD1306 display
 platform = ${com.esp32_platform}
 board = heltec_wifi_lora_32
 lib_deps =
   ${com-esp.lib_deps}
   ${libraries.wifimanager32}
   ${libraries.lora}
+  ${libraries.ssd1306} 
 build_flags =
   ${com-esp.build_flags}
+  ; *** OpenMQTTGateway Modules ***
+  '-DZboardHELTEC="HELTEC"'
+  '-DLOG_TO_LCD=true'         ; Enable log to LCD
+  ;  '-DLOG_LEVEL_LCD=LOG_LEVEL_TRACE'    // default is notice log level
   '-DZgatewayLORA="LORA"'
   '-DLORA_BAND=915E6'
   '-DGateway_Name="OpenMQTTGateway_ESP32_LORA"'