SSL support

[Misiu]

Hi there, I've noticed that in readme You wrote that HTTPS isn't supported. In similar project (Espurna) I found some interesting methods https://github.com/xoseperez/espurna/blob/master/code/espurna/web.ino#L330

#if ASYNC_TCP_SSL_ENABLED & WEB_SSL_ENABLED
    _server->onSslFileRequest(_onCertificate, NULL);
    _server->beginSecure("server.cer", "server.key", NULL);
#else
    _server->begin();
#endif

It look like ESPAsyncWebServer supports SSL. Maybe this can be added to Your project?

Did You solve 2 Factor Authentication? It would be awesome to have this supported via Google Authenticator App.