Add integration test and/or workshop example for AMQP and Nats connectors

[mfelsche]

Describe the problem you are trying to solve

When upgrading dependencies of connectors for which we have no automated testing in CI, we might break support with each update as connectivity is not tested.

Describe the solution you'd like

A docker based integration test for each connector (onramp/offramp) with external systems would be great. A working workshop example would work too, so we could manually test upon each new release. Having both would be gold standard.