migrated the codebase to Qt6 and fixed some compatibility issues

* used a Qt6 ported version of SortFilterProxyModel
* used an updated Qt6 compatible version of QXZing
* added a flag to windows linker to avoid WinMain problem of MSVCRTD
* renamed utils.cpp to utilities.cpp for avoiding confusion with the same file name in SortFilterProxyModel

client/ui/pages_logic/protocols/OtherProtocolsLogic.cpp

@@ -8,7 +8,7 @@
 #include "core/servercontroller.h"
 #include <functional>
 #include "../../uilogic.h"
-#include "utils.h"
+#include "utilities.h"
 
 #ifdef Q_OS_WINDOWS
 #include <Windows.h>
@@ -147,7 +147,7 @@ void OtherProtocolsLogic::onPushButtonSftpMountDriveClicked()
 //#ifndef Q_OS_WIN
 //    args.replace("reconnect-orellinks", "");
 //#endif
-    p->setArguments(args.split(" ", QString::SkipEmptyParts));
+    p->setArguments(args.split(" ", Qt::SkipEmptyParts));
     p->start();
     p->waitForStarted(50);
     if (p->state() != QProcess::Running) {