Add getter for SSID and password accessible from external of the WiFiManager class. (#97)

(cherry picked from commit c7d350a52bcb9fc52e61a2a3a8cdfe9db3d08bcf)

src/ESPAsyncWiFiManager.h

@@ -188,6 +188,13 @@ public:
   // sets a custom element to add to options page
   void setCustomOptionsElement(const char *element);
 
+  String getConfiguredSTASSID(){
+      return _ssid;
+  }
+  String getConfiguredSTAPassword(){
+      return _pass;
+  }
+
 private:
   AsyncWebServer *server;
 #ifdef USE_EADNS