Create Synchronous Message Tutorial

Synchronous/messages were made available in Pact-Specification V4.

https://github.com/pact-foundation/pact-specification/tree/version-4?tab=readme-ov-file#synchronousmessages

We should aim to demonstrate them in a workshop and identify any implementation gaps in either the core implementations (pact-rust / pact-jvm) or any of the client language DSL's
