Provide functions to produce Arrow PyCapsules

[wjones127]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

Follow up to #5070

Applications and libraries will want to support the Arrow PyCapsule Interface. We should provide some functions or maybe even classes to support that.

Describe the solution you'd like

Describe alternatives you've considered

Additional context

[pitrou]

Helper functions would probably be enough, as it's simply a matter of returning a PyO3 PyObject for a given Rust Schema or RecordBatch.

[kylebarron]

FWIW I published pyo3-arrow, a helper library to consume and create Arrow PyCapsules according to the Arrow PyCapsule interface