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/compilationdatabaseprojectmanager/compilationdatabaseutils.h

@@ -27,7 +27,7 @@
 
 #include "compilationdatabaseconstants.h"
 
-#include <cpptools/cppprojectfile.h>
+#include <cppeditor/cppprojectfile.h>
 #include <utils/fileutils.h>
 
 #include <QHash>
@@ -64,7 +64,7 @@ void filteredFlags(const QString &fileName,
                    QStringList &flags,
                    QVector<ProjectExplorer::HeaderPath> &headerPaths,
                    QVector<ProjectExplorer::Macro> &macros,
-                   CppTools::ProjectFile::Kind &fileKind,
+                   CppEditor::ProjectFile::Kind &fileKind,
                    QString &sysRoot);
 
 QStringList splitCommandLine(QString commandLine, QSet<QString> &flagsCache);