add admin command to delete individual media files

src/database/key_value/media.rs

@@ -140,4 +140,25 @@ impl service::media::Data for KeyValueDatabase {
         let parts = MediaFileKeyParts::try_from(&key)?;
         Ok((parts.meta, key))
     }
+
+    fn delete_file_metadata(&self, key: MediaFileKey) -> Result<()> {
+        self.mediaid_file.remove(key.as_bytes())
+    }
+
+    fn search_thumbnails_metadata(
+        &self,
+        mxc: OwnedMxcUri,
+    ) -> Result<Vec<(FileMeta, MediaFileKey)>> {
+        let mut prefix = mxc.as_bytes().to_vec();
+        prefix.push(0xFF);
+
+        self.mediaid_file
+            .scan_prefix(prefix)
+            .map(|(key, _)| {
+                let key = MediaFileKey::new(key);
+                let parts = MediaFileKeyParts::try_from(&key)?;
+                Ok((parts.meta, key))
+            })
+            .collect()
+    }
 }