ProjectExplorer: Add a "product" tag to the ProjectNode class

A product is a project node from which a target binary is produced, such
as a Product item in qbs or a .pro file in qmake.

Change-Id: I6a0e6bed6c02684cb03b2b18fed6a1b493fa78b2
Reviewed-by: hjk <hjk@qt.io>

src/plugins/cmakeprojectmanager/cmakeprojectnodes.cpp

@@ -173,6 +173,7 @@ CMakeTargetNode::CMakeTargetNode(const Utils::FileName &directory, const QString
     setPriority(Node::DefaultProjectPriority + 900);
     setIcon(QIcon(":/projectexplorer/images/build.png")); // TODO: Use proper icon!
     setListInProject(false);
+    setIsProduct();
 }
 
 QString CMakeTargetNode::generateId(const Utils::FileName &directory, const QString &target)