Currently, taking a snapshot of the metadata database with sqlite creates
a sqlite file without extension with the following format:
snapshots/2025-01-26T15:29:17Z
This makes it hard to understand what kind of data this is, and is not
consistent with LMDB:
snapshots/2025-01-26T15:29:17Z/data.mdb
With this change, we now get a directory with a single db.sqlite file:
snapshots/2025-01-26T15:29:17Z/db.sqlite