Add support for external disk backup - detect if disk is connected or not before backup
Add support to backup external disk on all operating system.
User's might want to backup an external disk using Minarca. When doing that, minarca will backup the disk in the same repository which is not a perfect solution because the disk might or might not be connected to the computer when the backup start. If the backup completes, data will be removed from the server.
We should have a mechanism to identify external disk. Make sure to backup external disk in different repositories. Start the backup if-and-only-if the disk is plugged.
Edited by Patrik Dufresne