Revamp Local Fortune Server Example: Fix includes

Fix include order to respect the Coding Conventions.

Add needed includes to avoid Transitive includes.

Remove uneeded classes.

Remove QT_{BEGIN,END}_NAMESPACE because these are private Qt macros that
should not be used in the examples.

Task-number: QTBUG-117064
Pick-to: 6.6 6.5
Change-Id: Ie98d4fbddb18d5578e2651bdb4850527ff984582
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>

examples/corelib/ipc/localfortuneserver/main.cpp

@@ -1,10 +1,10 @@
 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
-#include <QApplication>
-
 #include "server.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);

examples/corelib/ipc/localfortuneserver/server.cpp

@@ -3,8 +3,13 @@
 
 #include "server.h"
 
-#include <QtWidgets>
-#include <QtNetwork>
+#include <QGuiApplication>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QLocalSocket>
+#include <QMessageBox>
+#include <QPushButton>
+#include <QRandomGenerator>
 
 Server::Server(QWidget *parent)
     : QDialog(parent)

examples/corelib/ipc/localfortuneserver/server.h

@@ -5,12 +5,7 @@
 #define SERVER_H
 
 #include <QDialog>
-
-QT_BEGIN_NAMESPACE
-class QLabel;
-class QPushButton;
-class QLocalServer;
-QT_END_NAMESPACE
+#include <QLocalServer>
 
 class Server : public QDialog
 {