Utils: Wrap various file system iteration flags and filters

... into a single class.

This makes passing them around as a whole easier, and opens a path
to have "generic" filters in form of a lambda or such.

Change-Id: Ibf644b2fedcf0f1a35258030710afff8f5873f88
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/debugger/gdb/gdbengine.cpp

@@ -1615,9 +1615,7 @@ QString GdbEngine::cleanupFullName(const QString &fileName)
                     }
                     return true;
                 },
-                {"*"},
-                QDir::NoFilter,
-                QDirIterator::Subdirectories);
+                {{"*"}, QDir::NoFilter, QDirIterator::Subdirectories});
         }
     }