Add Python DynamoDB examples that use client instead of resource

[Laren-AWS]

The Boto3 team has officially ended support for the resource model, but all examples were written to use the resource model.

We had earlier discussed doing this, but set it aside as low priority. I now have a customer feedback request for this, so I'm adding it back for consideration.

[github-actions[bot]]

Marked stale by the Shirriff. Notifying @awsdocs/aws-sdk-docs-code-maintainers