[libcalamares] Convenience function YAML->QStringList

- operator>> already existed, but here's a version that
   can be used in function-call context.

src/libcalamares/utils/YamlUtils.cpp

@@ -109,6 +109,14 @@ yamlMapToVariant( const YAML::Node& mapNode )
     return vm;
 }
 
+QStringList
+yamlToStringList(const YAML::Node& listNode)
+{
+    QStringList l;
+    listNode >> l;
+    return l;
+}
+
 
 void
 explainYamlException( const YAML::Exception& e, const QByteArray& yamlData, const char *label )

src/libcalamares/utils/YamlUtils.h

@@ -32,6 +32,7 @@ class Node;
 class Exception;
 }
 
+/// @brief Appends all te elements of @p node to the string list @p v
 void operator>>( const YAML::Node& node, QStringList& v );
 
 namespace CalamaresUtils
@@ -51,6 +52,9 @@ QVariant yamlScalarToVariant( const YAML::Node& scalarNode );
 QVariant yamlSequenceToVariant( const YAML::Node& sequenceNode );
 QVariant yamlMapToVariant( const YAML::Node& mapNode );
 
+/// @brief Returns all the elements of @p listNode in a StringList
+QStringList yamlToStringList( const YAML::Node& listNode );
+
 /// @brief Save a @p map to @p filename as YAML
 bool saveYaml( const QString& filename, const QVariantMap& map );