Move Converter class, in eponymous example, to a file of its own

There's more details coming and it's good hygiene anyway.

Task-number: QTBUG-111228
Change-Id: Ief3acf6e508bc93eaa8490f6c49300b25c1d3556
Reviewed-by: Juha Vuolle <juha.vuolle@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 8b8fc42f2c6b08097bcd04038ed7f12667a90875)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 73a2f1edbc7bdb87a0936d65d2e58e1f9f831b20)

examples/corelib/serialization/convert/CMakeLists.txt

@@ -20,7 +20,7 @@ qt_standard_project_setup()
 
 qt_add_executable(convert
     cborconverter.cpp cborconverter.h
-    converter.h
+    converter.cpp converter.h
     datastreamconverter.cpp datastreamconverter.h
     debugtextdumper.cpp debugtextdumper.h
     jsonconverter.cpp jsonconverter.h

examples/corelib/serialization/convert/convert.pro

@@ -11,6 +11,7 @@ target.path = $$[QT_INSTALL_EXAMPLES]/corelib/serialization/convert
 INSTALLS += target
 
 SOURCES += main.cpp \
+    converter.cpp \
     cborconverter.cpp \
     datastreamconverter.cpp \
     debugtextdumper.cpp \

examples/corelib/serialization/convert/converter.cpp

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "converter.h"
+
+Converter::Converter()
+{
+    converters().append(this);
+}
+
+Converter::~Converter()
+{
+    converters().removeAll(this);
+}
+
+QList<const Converter *> &Converter::converters()
+{
+    Q_CONSTINIT static QList<const Converter *> store;
+    return store;
+}
+
+const QList<const Converter *> &Converter::allConverters()
+{
+    return converters();
+}

examples/corelib/serialization/convert/main.cpp

@@ -14,27 +14,6 @@
 
 using namespace Qt::StringLiterals;
 
-Converter::Converter()
-{
-    converters().append(this);
-}
-
-Converter::~Converter()
-{
-    converters().removeAll(this);
-}
-
-QList<const Converter *> &Converter::converters()
-{
-    Q_CONSTINIT static QList<const Converter *> store;
-    return store;
-}
-
-const QList<const Converter *> &Converter::allConverters()
-{
-    return converters();
-}
-
 static const Converter *prepareConverter(QString format, Converter::Direction direction,
                                          QFile *stream)
 {