(pipes-targets): Add Step functions target for EventBridge pipes

[RaphaelManke]

Describe the feature

Add a implementation for the Step function target for EventBridge pipes in the pipes-targets module.

Use Case

For feature completeness of the L2 pipes module this source is required

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

Environment details (OS name and version, etc.)

[RaphaelManke]

I will implement this target myself.

[tim-finnigan]

Thanks for the feature request and looking forward to seeing your PR!