Utils: Merge BaseAspects and AspectContainer

They were quite similar, largest difference was the ownership of
subaspects, which is now handled by a bool property.

Change-Id: Ib3f2f20b9a84ef40ea8a9eb59da9c89c9a281750
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/projectconfiguration.cpp

@@ -43,6 +43,8 @@ ProjectConfiguration::ProjectConfiguration(QObject *parent, Utils::Id id)
     : QObject(parent)
     , m_id(id)
 {
+    m_aspects.setOwnsSubAspects(true);
+
     QTC_CHECK(parent);
     QTC_CHECK(id.isValid());
     setObjectName(id.toString());