feat(pyo3-geoarrow): add add_triangle and add_line for BoundingRect

[ddupg]

No description provided.

[kylebarron]

I've been on vacation and add conferences, hence the slow review. Thanks!

Did you actually hit this todo! panic yourself? I wouldn't have imagined that it would be possible to hit that todo there.

Ideally I'd like to move this bounding rect computation and similar things into a geoarrow-expr-native crate. I'd like to have a place to start assembling utilities that don't fit into geoarrow-array or geoarrow-cast, but that are specified as not having a dependency on geo or geos.

If you're interested you'd be welcome to start creating that crate.

For now I'll merge this though, thanks!