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/python/pythonproject.cpp

@@ -50,6 +50,7 @@
 
 #include <utils/algorithm.h>
 #include <utils/fileutils.h>
+#include <utils/mimeutils.h>
 
 using namespace Core;
 using namespace ProjectExplorer;