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/basefilewizard.cpp

@@ -84,7 +84,7 @@ void BaseFileWizard::accept()
     QString errorMessage;
 
     // Compile result list and prompt for overwrite
-    switch (m_factory->promptOverwrite(&m_files, &errorMessage)) {
+    switch (BaseFileWizardFactory::promptOverwrite(&m_files, &errorMessage)) {
     case BaseFileWizardFactory::OverwriteCanceled:
         reject();
         return;