SSL Echo Client doesn't actually use SSL

The SSL Echo Server/Client example is meant to demonstrate how to set up a secure local WebSocket channel. The example server uses a self-signed certificate. The example client, however, does not set this certificate - in fact it does not do any SSL configuration at all, and explicitly ignores all SSL errors. This is a bit underwhelming.

Note that there is a complete other set of examples (Echo Server/Client) demonstrating non-secure WebSocket communication, so the only reason anyone would look at this example is to find out how the SSL configuration works - which the example then utterly fails to demonstrate.

To fix, this, the following would have to be added to the SslEchoClient constructor:

    QSslConfiguration sslConfiguration;
    sslConfiguration.setPeerVerifyMode(QSslSocket::VerifyPeer);
    QFile certFile(QStringLiteral(":/localhost.cert"));
    assert(certFile.open(QIODevice::ReadOnly));
    QSslCertificate certificate(&certFile, QSsl::Pem);
    certFile.close();
    sslConfiguration.addCaCertificate(certificate);
    m_webSocket.setSslConfiguration(sslConfiguration);

and of course the localhost.cert file from the server added to the client's resources.