backup: switch over to streaming Iterator improving memory usage

Avoid collecting the whole group list in memory only to iterate and
filter over it again.

Note that the change could result in a indentation change, so best
viewed with `-w` flag.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

src/backup/verify.rs

@@ -537,9 +537,8 @@ pub fn verify_all_backups(
         }
     };
 
-    let mut list = match verify_worker.datastore.list_backup_groups() {
+    let mut list = match verify_worker.datastore.iter_backup_groups_ok() {
         Ok(list) => list
-            .into_iter()
             .filter(|group| !(group.backup_type() == "host" && group.backup_id() == "benchmark"))
             .filter(filter_by_owner)
             .collect::<Vec<BackupGroup>>(),