file-restore-daemon: add disk module

Includes functionality for scanning and referring to partitions on
attached disks (i.e. snapshot images).

Fairly modular structure, so adding ZFS/LVM/etc... support in the future
should be easy.

The path is encoded as "/disk/bucket/component/path/to/file", e.g.
"/drive-scsi0/part/0/etc/passwd". See the comments for further
explanations on the design.

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>

src/bin/proxmox_restore_daemon/mod.rs

@@ -6,3 +6,6 @@ pub mod auth;
 
 mod watchdog;
 pub use watchdog::*;
+
+mod disk;
+pub use disk::*;