add admin command to delete all remote media files

src/database/key_value/media.rs

@@ -161,4 +161,27 @@ impl service::media::Data for KeyValueDatabase {
             })
             .collect()
     }
+
+    fn all_file_metadata(
+        &self,
+    ) -> Box<
+        dyn Iterator<Item = Result<(OwnedMxcUri, FileMeta, MediaFileKey)>> + '_,
+    > {
+        Box::new(
+            self.mediaid_file
+                .iter()
+                .map(|(key, _)| {
+                    let key = MediaFileKey::new(key);
+
+                    let parts = MediaFileKeyParts::try_from(&key)?;
+                    if parts.width != 0 && parts.height != 0 {
+                        // Skip thumbnails
+                        return Ok(None);
+                    };
+
+                    Ok(Some((parts.mxc, parts.meta, key)))
+                })
+                .filter_map(Result::transpose),
+        )
+    }
 }