Provide mnesia_rocksdb:backup/1,2 and restore/1,2 that pair a Mnesia
checkpoint (schema and non-RocksDB tables) with RocksDB backup engines
for open admin and standalone databases.
Restore stages RocksDB into a sibling directory and redirects mountpoints
while Mnesia fallback purges the real directory, then relocates the data
and optionally restarts. Raise the minimum OTP version to 27.
Ulf Wiger