Handle native geometry field name when reading from data sources that support alternative names

[brendan-ward]

We always use geometry as the geometry field name when reading from a data source, even if the data source uses a different name for geometry, which could be confusing when displaying the native geometry name in read_info as per #365.

This likely has implications for data sources with multiple geometries.

Users likely rely on the geometry column of a GeoDataFrame being named geometry, so we need to define desirable behavior in this case.

• expose a keyword parameter when reading? E.g., use_native_geometry_name (or something less verbose)
• automatically use native geometry name but raise warning if not geometry?
• detect if native geometry name is not geometry and raise warning, but continue to use geometry (could be combined with parameter above)

Reading additional geometry columns would likely use their native names, correct?