[packagechooser] Add stub of module

Package chooser is a **low density** package selector -- unlike
netinstall which offers a high density tree view -- for picking
zero, one, or more items from a small collection of packages.

This can be used, e.g., for "pick exactly one desktop environment",
"pick zero or more text editors" which can then be installed
by another module. The UI is big and shiny (rather than netinstall's
text-based tree view) and isn't suitable for more than a dozen or
so items.

src/modules/packagechooser/PackageChooserViewStep.cpp

@@ -0,0 +1,113 @@
+/* === This file is part of Calamares - <https://github.com/calamares> ===
+ *
+ *   Copyright 2019, Adriaan de Groot <groot@kde.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "PackageChooserViewStep.h"
+
+#include "PackageChooserPage.h"
+
+#include "GlobalStorage.h"
+#include "JobQueue.h"
+
+#include "utils/CalamaresUtilsSystem.h"
+#include "utils/Logger.h"
+#include "utils/Variant.h"
+
+#include <QDesktopServices>
+#include <QVariantMap>
+
+CALAMARES_PLUGIN_FACTORY_DEFINITION( PackageChooserViewStepFactory, registerPlugin< PackageChooserViewStep >(); )
+
+PackageChooserViewStep::PackageChooserViewStep( QObject* parent )
+    : Calamares::ViewStep( parent )
+    , m_widget( nullptr )
+{
+    emit nextStatusChanged( false );
+}
+
+
+PackageChooserViewStep::~PackageChooserViewStep()
+{
+    if ( m_widget && m_widget->parent() == nullptr )
+    {
+        m_widget->deleteLater();
+    }
+}
+
+
+QString
+PackageChooserViewStep::prettyName() const
+{
+    return tr( "Packages" );
+}
+
+
+QWidget*
+PackageChooserViewStep::widget()
+{
+    if ( !m_widget )
+    {
+        m_widget = new PackageChooserPage( nullptr );
+    }
+    return m_widget;
+}
+
+
+bool
+PackageChooserViewStep::isNextEnabled() const
+{
+    return true;
+}
+
+
+bool
+PackageChooserViewStep::isBackEnabled() const
+{
+    return true;
+}
+
+
+bool
+PackageChooserViewStep::isAtBeginning() const
+{
+    return true;
+}
+
+
+bool
+PackageChooserViewStep::isAtEnd() const
+{
+    return true;
+}
+
+
+void
+PackageChooserViewStep::onLeave()
+{
+}
+
+Calamares::JobList
+PackageChooserViewStep::jobs() const
+{
+    Calamares::JobList l;
+    return l;
+}
+
+void
+PackageChooserViewStep::setConfigurationMap( const QVariantMap& configurationMap )
+{
+}