improve documentation(#524)

add wifi manager portal screenshots
add M5stick
correct bad link
improve lora doc

docs/upload/portal.md

@@ -2,13 +2,24 @@
 
 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.
 From your smartphone search for your OpenMQTTGateway wifi network and connect to it, a web page will appear
+
+![Wifi manager menu](../img/OpenMQTTGateway_Wifi_Manager_menu.png)
+
+* Click on Configure WiFi
+
+![Wifi manager parameters](../img/OpenMQTTGateway_Wifi_Manager_enter_parameters.png)
+
 * Select your wifi
 * Set your wifi password
 * Set your MQTT Server IP
-* Set your MQTT Server username (not compulsory)
-* Set your MQTT Server password (not compulsory)
-* Set your MQTT base topic (you must keep the / at the end)
-* Set your gateway name
+* Set your MQTT Server username (facultative)
+* Set your MQTT Server password (facultative)
+* Set your MQTT base topic if you need to change it (you must keep the / at the end)
+* Set your gateway name if you need to change it
+
+* Click on save
+
+![Wifi manager save](../img/OpenMQTTGateway_Wifi_Manager_save.png)
 
 The ESP restart and connect to your network. Note that your credentials are saved into the ESP memory, if you want to redo the configuration you have to erase the ESP memory with the flash download tool.
 
@@ -20,5 +31,4 @@ home/OpenMQTTGateway/LWT Online
 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_PIN.
-
+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_PIN or [erase the settings](../use/gateway.md#erase-the-esp-settings).