Support geospatial statistics and bounding box metadata

[gunnarmorling]

Add support for reading geospatial metadata from Parquet files:

• GeospatialStatistics in ColumnMetaData (field 17) — per-column geospatial stats
• BoundingBox — min/max bounds for X, Y, and optional Z/M dimensions
• geospatial_types — list of geometry type codes present in the column

This is a prerequisite for spatial predicate pushdown on Geometry/Geography columns.

[mghildiy]

I can take it up.

[mghildiy]

Raised PR for this.