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/clangtools/clangtoolsprojectsettingswidget.cpp

@@ -33,13 +33,13 @@
 #include "clangtoolsutils.h"
 
 #include <coreplugin/icore.h>
-#include <cpptools/clangdiagnosticconfigsselectionwidget.h>
+#include <cppeditor/clangdiagnosticconfigsselectionwidget.h>
 
 #include <utils/qtcassert.h>
 
 #include <QAbstractTableModel>
 
-#include <cpptools/clangdiagnosticconfigsmodel.h>
+#include <cppeditor/clangdiagnosticconfigsmodel.h>
 
 namespace ClangTools {
 namespace Internal {
@@ -108,7 +108,7 @@ ProjectSettingsWidget::ProjectSettingsWidget(ProjectExplorer::Project *project,
         m_projectSettings->setRunSettings(m_ui->runSettingsWidget->toSettings());
 
         // Save global custom configs
-        const CppTools::ClangDiagnosticConfigs configs
+        const CppEditor::ClangDiagnosticConfigs configs
             = m_ui->runSettingsWidget->diagnosticSelectionWidget()->customConfigs();
         ClangToolsSettings::instance()->setDiagnosticConfigs(configs);
         ClangToolsSettings::instance()->writeSettings();