Nested digital twins

[caviri]

Context
A powerful idea is to be able to embed digital twins into other digital twins. This nesting is not supported right now.

The idea is to give the possibility to embed a digital twin into another and so on. These digital twins can act as "components" when designed the execution workflow.

Proposed solution
We can place smaller, detailed digital twins inside larger ones, kind of like nesting dolls. In this case the new digital twin can be used as an input/output blackbox in a similar way to a component. These smaller twins are set up based on specific rules and checks to make sure they 'talk' correctly to the larger twin they're inside of. Also, the smaller twins should be less detailed than the larger ones they fit into.

Acceptance criteria

• Develop strategy to allow nesting of digital twins based on components.
• Update digitalTwin schema to include semantic input/output
• Implement in ODTP
• Run a simple test with one level DT nesting