WiFi: add SSID() and RSSI()

Author: pennam

libraries/SocketWrapper/WiFi.h

@@ -99,12 +99,28 @@ class WiFiClass : public NetworkInterface {
 		// TODO: borrow code from mbed core for scan results handling
 	}
 
+    char* SSID() {
+        if (status() == WL_CONNECTED) {
+            return (char *)sta_state.ssid;
+        }
+        return nullptr;
+    }
+
+    int32_t RSSI() {
+        if (status() == WL_CONNECTED) {
+            return sta_state.rssi;
+        }
+        return 0;
+    }
+
 private:
 	struct net_if *sta_iface = nullptr;
 	struct net_if *ap_iface = nullptr;
 
 	struct wifi_connect_req_params ap_config;
 	struct wifi_connect_req_params sta_config;
+
+    struct wifi_iface_status sta_state = { 0 };
 };
 
 extern WiFiClass WiFi;