Example: Compare RuleUnit coordination to KieBase composition

KIE v7 allowed composition of KIE Bases.
This is currently not possible with Rule Units.

Show instead, in an example, how to coordinate Rule Units and show how this compares to composition of KIE Bases.

The goal of this example is to show that use cases where v7 composed KIE Bases are improved/better/equivalent to use cases where Rule Units are coordinated.

e.g. it should be shown that data can be shared using shared Data Sources.

the goal is also to assess if this is more cumbersome not only to use, but also to understand, than composition, and thus decide if we want to bring composition in some form to Rule Units too