Implemented: EZP-23045: In the admin interface: make it possible to sort by visibility

Issue link: https://jira.ez.no/browse/EZP-23045

When there is a lot of children under a specific content (object), not being able to sort by visibility makes it a bit difficult to quickly see which one are hidden for example, or perform bulk operations (like remove) on those: one has to click on every page from the google-like navigator to discover them.
With visibility sorting, it makes it a bit easier.