GeoParquet files to support ancillary fields

[jpswinski]

The current ParquetBuilder class does not support buffering records and associating ancillary fields (neither from ATL03 nor fromArcticDEM).

I recommend providing a plugin-like feature (i.e. callback) to the EndpointProxy that buffers results and builds a GeoParquet file. This callback can be implemented in the arrow package and installed as a part of the icesat2 plugin initialization.