[TECHNICAL-SUPPORT] LPS-33282 Page sorting in navigation has no permanent effect without having the required permission

Hi Tamás,

I'm resending this pull after rethinking the logic.
Page sorting is more than a simple action on a layout. It modifies the current page order of a given site, so it's like an administrative change. 

We should enable or disable it based on a GroupPermission check, like MANAGE_LAYOUTS, as we do in Site Pages portlet.
If the current user doesn't have this permission, we should not allow to sort any pages.

Let me know if you have any concern.

Thanks,
Tibor