Add benchmark tests for machine creation latency

## What is your idea?
Add benchmark tests for machine creation latency

## Would you be willing to make the change?
Maybe

## Additional context
https://github.com/aws/event-ruler/pull/104

Start by reviewing pull request #104 and the repository's existing test and benchmark setup for machine creation. Determine where machine creation is exercised and what latency measurements are expected; done means benchmark tests covering that operation are added and can run with the project's test tooling.

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