Add ESP32 Olimex ethernet gateway (#747)

-Add ethernet board
-Add wifi board
-Add ethernet management for ESP32

docs/upload/portal.md

@@ -1,6 +1,8 @@
-# Wifi and MQTT configuration portal
+# Wifi and MQTT configuration
 
-Once loaded into your board and if you don't use the manual configuration you have to set your network parameters with wifi manager portal.
+## Wifi and MQTT configuration portal for Wifi boards
+
+Once loaded into your ESP and if you don't use the manual configuration you have to set your network parameters with wifi manager portal.
 From your smartphone search for your OpenMQTTGateway wifi network and connect to it with `WifiManager_password` (the default password is "your_password"), a web page will appear.
 
 ![Wifi manager menu](../img/OpenMQTTGateway_Wifi_Manager_menu.png)
@@ -30,3 +32,27 @@ home/OpenMQTTGateway/version
 ```
 
 Note that the web portal appears only on first boot, if you want to configure again the setting you can do a long press on TRIGGER_GPIO or [erase the settings](../use/gateway.md#erase-the-esp-settings).
+
+## MQTT and network configuration for Ethernet and Wifi boards
+
+You can configure your MQTT server credentials and network configuration before building the application. It can be done either in Arduino or in Platformio IDE thought the User_config.h file. Note that with Platformio IDE you can also set your credentials into the platformio.ini file or an *_env.ini file, here is an example with the Olimex ESP32 gateway:
+
+``` ini
+[env:esp32-olimex-gtw-ble]
+platform = ${com.esp32_platform}
+board = esp32-gateway
+board_build.partitions = min_spiffs.csv
+lib_deps =
+  ${com-esp.lib_deps}
+  ${libraries.ble}
+build_flags =
+  ${com-esp.build_flags}
+  '-DZgatewayBT="BT"'
+  '-DLED_INFO=33'
+  '-DLED_INFO_ON=1'
+  '-DESP32_ETHERNET=true'
+  '-DMQTT_SERVER="11.22.33.44"'
+  '-DMQTT_USER="salut"'
+  '-DMQTT_PASS="atoi"'
+  '-DGateway_Name="OpenMQTTGateway_ESP32_OLM_GTW"'
+```