[Testing] Integration Tests and Examples

[dhegberg]

Migration from aws/aws-durable-execution-sdk-python-testing#61

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overview

Parent epic for sub-tasks that implement end-to-end integration tests and examples.

https://github.com/aws/aws-durable-execution-sdk-python-testing/tree/main/examples

For a start, create python versions of https://github.com/aws/aws-durable-execution-sdk-js/blob/development/packages/aws-durable-execution-sdk-js-examples

Integration tests should run against:

1. LocalRunner
2. Actual backend