add protected info of snapshots to api and task logs

adds the info that a snapshot is protected to:
* snapshot list
* manual pruning (also dry-run)
* prune jobs

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

pbs-api-types/src/datastore.rs

@@ -390,6 +390,8 @@ pub struct SnapshotListItem {
     /// The owner of the snapshots group
     #[serde(skip_serializing_if = "Option::is_none")]
     pub owner: Option<Authid>,
+    /// Protection from prunes
+    pub protected: bool,
 }
 
 #[api(