Provide configuration kits for tutorial ECA models

Problem/Motivation

We expect to get quite some support requests asking if and how to achieve certain things with ECA. Rather than explaining possible solutions paths, it will be helpful to setup a quick ECA model, actually demonstrating how things work. To deliver such an example model, not only the model and ECA config files might be necessary, but also their dependencies.

Let's find out, how to best create config kits, that are self-contained and only need to be imported to review them on remote Drupal sites. Some ideas might be found in the Config Kit module.