Detect first startup (after installation) and show a instruction or so

[github-actions]

https://api.github.com/tim-gromeyer/VoiceAssistant/blob/e182eaebd2c538b1a31b5ef4950873f1943e9d3e/src/mainwindow.cpp#L144

    player->setAudioOutput(audioOutput);
#endif

    // TODO: Detect first startup (after installation) and show a instruction or so
    firstSetup();

    // Set up recognizer
    recognizer = new SpeechToText(STR("vosk"), this);
    connect(recognizer, &SpeechToText::stateChanged, this, &MainWindow::onSTTStateChanged);