CMakePM: Start integrating ctest

Gather some more information of a CMake based project to be
able to provide this later on to the AutoTest plugin.

Task-number: QTCREATORBUG-23332
Change-Id: I2beaf0a6456d57871dcf65832f0a79f37fe5fddc
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/cmakeprojectmanager/fileapidataextractor.h

@@ -54,6 +54,7 @@ public:
     ProjectExplorer::RawProjectParts projectParts;
     std::unique_ptr<CMakeProjectNode> rootProjectNode;
     QSet<Utils::FilePath> knownHeaders;
+    QString ctestPath;
 };
 
 FileApiQtcData extractData(FileApiData &data,