reference the datastore in BackupGroup/Dir

And drop the base_path parameter on a first bunch of
functions (more reordering will follow).

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/backup/verify.rs

@@ -450,7 +450,7 @@ pub fn verify_backup_group(
     filter: Option<&dyn Fn(&BackupManifest) -> bool>,
 ) -> Result<Vec<String>, Error> {
     let mut errors = Vec::new();
-    let mut list = match group.list_backups(&verify_worker.datastore.base_path()) {
+    let mut list = match group.list_backups() {
         Ok(list) => list,
         Err(err) => {
             task_log!(