Item storage: Permissions aren't stored in the items anymore (#5495)

Item storage: Permissions aren't stored in the items anymore (#5495)

* The permission set is now used for item permissions

* Check for allow_cid, ... is superfluous. Checking for "private" is enough

* We query the permissionset

* Permissions are displayed correctly

* Changed index

* We don't store the permissions in the item table anymore

* Permission fields are now deprecated

* Reversed ...