Add more realistic bulk import example

[tstirrat15]

Description

We've gotten a couple of questions around the behavior of ImportBulkRelationships and how to do batching with it. This is intended as an example of a slightly-more-real-world batching strategy. I intended to use it in the documentation, but I hadn't considered that the python client speaks in terms of iterators, which is pythonic but not easily grokkable for non-python devs, so I won't use this example in the documentation, but it'll probably be helpful to have it in the examples dir.

Changes

• Add a new example file

Testing

Start a serve-testing instance and run the example against it

[alecmerdler]

Thanks for adding this!