[netinstall] Build up a list of urls, rather than just one

- the list is unused, and doesn't drive the loading of groups either;
  the existing one-string entry is used.

src/modules/netinstall/Config.cpp

@@ -170,6 +170,19 @@ Config::receivedGroupData()
     }
 }
 
+Config::SourceItem Config::SourceItem::makeSourceItem(const QVariantMap& configurationMap, const QString& groupsUrl)
+{
+    if ( groupsUrl == QStringLiteral( "local" ) )
+    {
+        return SourceItem{ QUrl(), configurationMap.value( "groups" ).toList() };
+    }
+    else
+    {
+        return SourceItem{ QUrl{ groupsUrl }, QVariantList() };
+    }
+}
+
+
 void
 Config::setConfigurationMap( const QVariantMap& configurationMap )
 {
@@ -193,6 +206,20 @@ Config::setConfigurationMap( const QVariantMap& configurationMap )
     }
 
     // Lastly, load the groups data
+    const QString key = QStringLiteral( "groupsUrl" );
+    const auto& groupsUrlVariant = configurationMap.value( key );
+    if ( groupsUrlVariant.type() == QVariant::String )
+    {
+        m_urls.append( SourceItem::makeSourceItem( configurationMap, groupsUrlVariant.toString() ) );
+    }
+    else if ( groupsUrlVariant.type() == QVariant::StringList )
+    {
+        for ( const auto& s : groupsUrlVariant.toStringList() )
+        {
+            m_urls.append( SourceItem::makeSourceItem( configurationMap, s ) );
+        }
+    }
+
     QString groupsUrl = CalamaresUtils::getString( configurationMap, "groupsUrl" );
     if ( !groupsUrl.isEmpty() )
     {

src/modules/netinstall/Config.h

@@ -18,6 +18,7 @@
 
 #include <QObject>
 #include <QUrl>
+#include <QQueue>
 #include <QVariantMap>
 
 class QNetworkReply;
@@ -85,6 +86,23 @@ private slots:
     void retranslate();
 
 private:
+    /** @brief Data about an entry in *groupsUrl*
+     *
+     * This can be a specific URL, or "local" which uses data stored
+     * in the configuration file itself.
+     */
+    struct SourceItem
+    {
+        QUrl url;
+        QVariantList data;
+
+        bool isUrl() const { return url.isValid(); }
+        bool isLocal() const { return !data.isEmpty(); }
+        bool isValid() const { return isUrl() || isLocal(); }
+        static SourceItem makeSourceItem( const QVariantMap& configurationMap, const QString& groupsUrl);
+    };
+
+    QQueue< SourceItem > m_urls;
     CalamaresUtils::Locale::TranslatedString* m_sidebarLabel = nullptr;  // As it appears in the sidebar
     CalamaresUtils::Locale::TranslatedString* m_titleLabel = nullptr;
     PackageModel* m_model = nullptr;