Re-export parquet-format

[nevi-me]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

We now return parquet_format::FileMetadata when closing a writer. For users to use this struct, they need to include parquet-format as a Cargo dependency.

This will cause problems if users import incompatible versions of the format crate.

Describe the solution you'd like

Re-export parquet_format as parquet::format, or export parts of the crate as required.

Describe alternatives you've considered

Probably the option to export the whole crate vs parts of it,

Additional context

None

[tustvold]

Closed by #2626