Create stub package published to PyPI named `geoarrow`

[kylebarron]

Aimed to prevent a future package from breaking our native namespacing by distributing a top-level geoarrow/__init__.py

[jorisvandenbossche]

Longer term this could also be a "meta" package that installs all separate pieces?

[kylebarron]

Yeah definitely! If you want the entire ecosystem, just pip install geoarrow (similar to pip install jupyter). Otherwise, install geoarrow-c or geoarrow-rs or whatever directly