add OTA support

main/WifiStation.h

@@ -11,12 +11,16 @@ public:
     bool IsConnected();
     std::string ssid() { return ssid_; }
     std::string ip_address() { return ip_address_; }
+    int8_t rssi() { return rssi_; }
+    uint8_t channel() { return channel_; }
 
 private:
     EventGroupHandle_t event_group_;
     std::string ssid_;
     std::string password_;
     std::string ip_address_;
+    uint8_t rssi_ = 0;
+    uint8_t channel_ = 0;
     int reconnect_count_ = 0;
 };