s/target/buildtarget/ in projectnodes

This is in preparation of the addition of "targets" in the sense
of "platforms to develop for" into the codebase.

Reviewed-by: dt

src/plugins/qmlprojectmanager/qmlprojectnodes.cpp

@@ -157,7 +157,7 @@ ProjectExplorer::FolderNode *QmlProjectNode::findOrCreateFolderByName(const QStr
     return findOrCreateFolderByName(components, components.length());
 }
 
-bool QmlProjectNode::hasTargets() const
+bool QmlProjectNode::hasBuildTargets() const
 {
     return true;
 }