Merge CppTools into CppEditor

There was no proper separation of responsibilities between these
plugins. In particular, CppTools had lots of editor-related
functionality, so it's not clear why it was separated out in the first
place.
In fact, for a lot of code, it seemed quite arbitrary where it was put
(just one example: switchHeaderSource() was in CppTools, wheras
switchDeclarationDefinition() was in CppEditor).
Merging the plugins will enable us to get rid of various convoluted
pseudo-abstractions that were only introduced to keep up the artificial
separation.

Change-Id: Iafc3bce625b4794f6d4aa03df6cddc7f2d26716a
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/cppeditor/cppfunctiondecldeflink.h

@@ -26,8 +26,7 @@
 #pragma once
 
 #include "cppquickfix.h"
-
-#include <cpptools/cpprefactoringchanges.h>
+#include "cpprefactoringchanges.h"
 
 #include <QString>
 #include <QCoreApplication>
@@ -98,7 +97,7 @@ public:
     int targetColumn = 0;
     QString targetInitial;
 
-    CppTools::CppRefactoringFileConstPtr targetFile;
+    CppRefactoringFileConstPtr targetFile;
     CPlusPlus::Function *targetFunction = nullptr;
     CPlusPlus::DeclarationAST *targetDeclaration = nullptr;
     CPlusPlus::FunctionDeclaratorAST *targetFunctionDeclarator = nullptr;