Utils/ProjectExplorer: Move re-usabled bits of aspects to Utils

Classes involved are BaseAspect and some derived classes,
LayoutBuilder and VariableChooser.

This is mostly mechanical, with various include/using changes
to make it compile.

Change-Id: I624a457f3555f102e541c4c71e33a9423af32250
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/qmakeprojectmanager/makefileparse.cpp

@@ -36,15 +36,15 @@
 #include <QTextStream>
 #include <QLoggingCategory>
 
-using namespace QmakeProjectManager;
-using namespace Internal;
 using namespace ProjectExplorer;
+using namespace Utils;;
 
-using Utils::FilePath;
-using Utils::QtcProcess;
 using QtSupport::QtVersionManager;
 using QtSupport::BaseQtVersion;
 
+namespace QmakeProjectManager {
+namespace Internal {
+
 static QString findQMakeLine(const QString &makefile, const QString &key)
 {
     QFile fi(makefile);
@@ -396,6 +396,8 @@ void MakeFileParse::parseCommandLine(const QString &command, const QString &proj
     }
 }
 
+} // Internal
+} // QmakeProjectManager
 
 // Unit tests: