Add popup information on successful group adds.

Migrated from: https://tracker.clearos.com/view.php?id=

Reported by: Dave Loper

Notify admin that re-login of Windows clients is necessary.

When adding a user to a group in the user or group apps, if windows networking or samba directory is installed, the following message will help to reduce support tickets and make the interface more intuitive:

"User added to group. Workstations using [Windows Networking|Samba Directory] must log out and in again for group membership to register with workstation profile."

Developer Comment:

In app-users note that you can manipulate multiple users in one transaction