add index recovery to pb-debug

Adds possibility to recover data from an index file. Options:
 - chunks: path to the directory where the chunks are saved
 - file: the index file that should be recovered(must be either .fidx or
   didx)
 - [opt] keyfile: path to a keyfile, if the data was encrypted, a keyfile is
   needed
 - [opt] skip-crc: boolean, if true, read chunks wont be verified with their
   crc-sum, increases the restore speed by a lot

Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/bin/proxmox_backup_debug/mod.rs

@@ -1,2 +1,4 @@
 mod inspect;
 pub use inspect::*;
+mod recover;
+pub use recover::*;