Allow hiding folders from the SAS server files that are mounted from the Studio Explorer pane

[bmcclelland]

In large enterprise organizations, it would be beneficial to be able to hide, or make visible, folders from the SAS server files that are mounted from the Studio Explorer pane based on the groups the users are in.

See Case: CS0115567 for the original support question and example.

[Kurt_Bremser]

The "invisibility cloak" has to be a directory which those users can't read; but they will still be able to see this one from the outside.