Code cosmetics

Mostly unused #include's, also sort them or reduce scope.

A few namespaces, ...

Change-Id: I9ee71e07de7157c9942125672addf87dd41e78f1
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/session.cpp

@@ -31,6 +31,7 @@
 #include "kit.h"
 #include "project.h"
 #include "projectexplorer.h"
+#include "projectexplorerconstants.h"
 #include "projectnodes.h"
 #include "target.h"
 
@@ -51,7 +52,6 @@
 #include <QDebug>
 #include <QDir>
 #include <QFileInfo>
-
 #include <QMessageBox>
 #include <QPushButton>