Add script to dump all data bundles from the database. (#4662)

Useful in the context of https://crbug.com/387828386 and to confirm
whether #4661 is safe to land.

Usage:

```
$ python butler.py run dump_data_bundles -c $CONFIG_DIR --script_arg bundles.csv
```

Author: letitz

src/local/butler/scripts/dump_data_bundles.py

@@ -0,0 +1,51 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Dumps data bundle metadata from the database in CSV format."""
+
+import csv
+
+from clusterfuzz._internal.datastore import data_types
+
+
+def _dump(f) -> None:
+  """Dumps data bundle metadata from the database to the given file."""
+  writer = csv.DictWriter(
+      f,
+      fieldnames=[
+          'name',
+          'bucket_name',
+          'source',
+          'timestamp',
+          'sync_to_worker',
+      ])
+  writer.writeheader()
+
+  for bundle in data_types.DataBundle.query():
+    writer.writerow({
+        'name': bundle.name,
+        'bucket_name': bundle.bucket_name,
+        'source': bundle.source,
+        'timestamp': str(bundle.timestamp),
+        'sync_to_worker': bundle.sync_to_worker,
+    })
+
+
+def execute(args):
+  """Dumps data bundle metadata from the database in CSV format."""
+  if not args.script_args or len(args.script_args) != 1:
+    print('Usage: dump_data_bundles --script_arg OUTPUT_FILE')
+    return
+
+  with open(args.script_args[0], 'w') as f:
+    _dump(f)