Add an hasSeries() Q_INVOKABLE method to Bars3D interface

bool    XXX::bars3DHasSeries(QBar3DSeries* series)
{
    bool hasSeries{false};
    if ( series != nullptr &&
	 getBars3D() != nullptr ) {
        QQmlProperty seriesListQmlProperty(getBars3D(), "seriesList");
        if ( seriesListQmlProperty.isValid() ) {
            QQmlListReference seriesList = qvariant_cast<QQmlListReference>( seriesListQmlProperty.read() );
            if (seriesList.isValid())
                for ( int s = 0; s < seriesList.count(); s++ )
                    if ( seriesList.at(s) == series ) {
                        hasSeries = true;
                        break;
                    }
        }
    }
    return hasSeries;
}