QmlProject: Detect import type from mainFile

Detect the default import (QtQuick 1.x vs QtQuick 2.x) from main
file, and use it to restrict kits + select the right runtime.

Task-number: QTCREATORBUG-8358
Change-Id: Ib8cfd3eb989953f607fee6043c43e588f798c774
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/qmlprojectmanager/qmlproject.h

@@ -92,6 +92,9 @@ public:
 
     void refreshProjectFile();
 
+    enum QmlImport { UnknownImport, QtQuick1Import, QtQuick2Import };
+    QmlImport defaultImport() const;
+
 private slots:
     void refreshFiles(const QSet<QString> &added, const QSet<QString> &removed);
     void addedTarget(ProjectExplorer::Target *target);
@@ -109,6 +112,7 @@ private:
     QString m_fileName;
     Internal::QmlProjectFile *m_file;
     QString m_projectName;
+    QmlImport m_defaultImport;
     QmlJS::ModelManagerInterface *m_modelManager;
 
     // plain format