tape: fix snapshot path in catalog and snapshot_archive

both used the 'Display' trait of pbs_datastore::BackupDir, which is not
intended to be serialized anywhere. Instead, manually format the path
using the print_ns_and_snapshot helper, and conversely, parse with
'parse_ns_and_snapshot'. to be a bit safer, change the register_snapshot
signature to take a BackupNamespace and BackupDir instead of a string.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

src/api2/tape/media.rs

@@ -438,7 +438,7 @@ pub fn list_content(
             .unwrap_or_else(|_| set.uuid.to_string());
 
         for (store, snapshot) in media_catalog_snapshot_list(status_path, &media_id)? {
-            let backup_dir: pbs_api_types::BackupDir = snapshot.parse()?;
+            let (_, backup_dir) = pbs_api_types::parse_ns_and_snapshot(&snapshot)?;
 
             if let Some(backup_type) = filter.backup_type {
                 if backup_dir.ty() != backup_type {