Allow "GeoParquet" input

[kylebarron]

Pyarrow assigns Parquet metadata onto the Arrow table metadata when it loads. So whenever you use pyarrow.parquet.read_table() on a GeoParquet file, you'll get a geo key in the table metadata. Even though this is not "GeoArrow" per se, because it's missing the geoarrow extension metadata on the column field, it would probably be good integration to look for the geo key and manage GeoParquet -> GeoArrow conversion.

This is something that would potentially be moved into a different geoarrow library in the future, but faster to prototype here.