Core: Make member functions const/static

readability-make-member-function-const finds lots of member functions
that could be made const. This change just picks getter functions that
really should be const.

readability-convert-member-functions-to-static finds non-static member
functions which do not access this. This change turns most of them
into static ones, but leaves some non static to keep the class API
consistent.

Change-Id: I004d6f7fab4375f9902f940f29b4a4f561fc7604
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/basefilewizardfactory.cpp

@@ -203,7 +203,7 @@ bool BaseFileWizardFactory::postGenerateOpenEditors(const GeneratedFiles &l, QSt
 */
 
 BaseFileWizardFactory::OverwriteResult BaseFileWizardFactory::promptOverwrite(GeneratedFiles *files,
-                                                                QString *errorMessage) const
+                                                                QString *errorMessage)
 {
     if (debugWizard)
         qDebug() << Q_FUNC_INFO << files;