Plugins: Code cosmetics

Get closer to a uniform pattern of code layout (public/private,
pimpl naming...)

Change-Id: If2bc6dcee3df9127274f479b4ebc270d283dcb65
Reviewed-by: Xing Xiong
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/cmakeprojectmanager/cmakeprojectplugin.h

@@ -26,8 +26,9 @@
 #pragma once
 
 #include "cmakespecificsettingspage.h"
+
 #include <extensionsystem/iplugin.h>
-#include <memory>
+
 namespace CMakeProjectManager {
 namespace Internal {