Add test for default install

With Online Installer version 4.0.0 onwards, there is a new feature called default install. It adds a new radiobutton set to target directory page. By default, 'Custom installation' is selected and the install is performed as usual - user must select the installable components.

Another option is 'Default desktop installation' which wil automatically select components for install and component selection page is skipped.

Note that all of these are defined in a repository (also the radio buttons) so the selected components may vary, there can be several components or no components at all. If there are no components defined in the repository or the repository is missing then no radiobuttons are visible. Please ask packaging team for status of this.

Here is the control script that will select the radio button 'Default desktop installation' and install is performed without component selection page:

Controller.prototype.TargetDirectoryPageCallback = function()
{
    var page = gui.pageWidgetByObjectName("TargetDirectoryPage");
    page.TargetDirectoryLineEdit.setText(installerTargetDirectory);
    var installTypeWidget = page.installTypeWidget
    if (installTypeWidget) {
        installTypeWidget.groupBox.defaultInstallRadioButton.checked = true;
    }
    gui.clickButton(buttons.NextButton);
}