wifi: add SoftAPModeProbeRequestReceived event handler (#2917)

- add probe request event handler (#2910)
- update WiFi events handling example to use new handler

Pro tip: replace blinking LED with ‘analogWrite’ and connect the pin to
a loudspeaker (or use a servo to hit a bell). Get notified when someone
with a smartphone wanders around your country house.

libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp

@@ -186,6 +186,19 @@ WiFiEventHandler ESP8266WiFiGenericClass::onSoftAPModeStationDisconnected(std::f
     return handler;
 }
 
+WiFiEventHandler ESP8266WiFiGenericClass::onSoftAPModeProbeRequestReceived(std::function<void(const WiFiEventSoftAPModeProbeRequestReceived&)> f)
+{
+    WiFiEventHandler handler = std::make_shared<WiFiEventHandlerOpaque>(WIFI_EVENT_SOFTAPMODE_PROBEREQRECVED, [f](System_Event_t* e){
+        auto& src = e->event_info.ap_probereqrecved;
+        WiFiEventSoftAPModeProbeRequestReceived dst;
+        memcpy(dst.mac, src.mac, 6);
+        dst.rssi = src.rssi;
+        f(dst);
+    });
+    sCbEventList.push_back(handler);
+    return handler;
+}
+
 // WiFiEventHandler ESP8266WiFiGenericClass::onWiFiModeChange(std::function<void(const WiFiEventModeChange&)> f)
 // {
 //     WiFiEventHandler handler = std::make_shared<WiFiEventHandlerOpaque>(WIFI_EVENT_MODE_CHANGE, [f](System_Event_t* e){

libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.h

@@ -61,6 +61,7 @@ class ESP8266WiFiGenericClass {
         WiFiEventHandler onStationModeDHCPTimeout(std::function<void(void)>);
         WiFiEventHandler onSoftAPModeStationConnected(std::function<void(const WiFiEventSoftAPModeStationConnected&)>);
         WiFiEventHandler onSoftAPModeStationDisconnected(std::function<void(const WiFiEventSoftAPModeStationDisconnected&)>);
+        WiFiEventHandler onSoftAPModeProbeRequestReceived(std::function<void(const WiFiEventSoftAPModeProbeRequestReceived&)>);
         // WiFiEventHandler onWiFiModeChange(std::function<void(const WiFiEventModeChange&)>);
 
         int32_t channel(void);