[Python] Adding a Substrait Example

Mirroring the C++ case for Python:

Add an example on substrait with a couple of features to expose Arrow compute capabilities.

Start by locating the existing C++ Substrait example and the Python cookbook examples it should mirror. Done means a Python Substrait example is added with a couple of features exposing Arrow compute capabilities; the issue does not name specific files or features.

Written by the indexing model from the issue text.