[Core] Add minimal NLU structure

[yuripourre]

Requirements + Meaning

Action can have a requirement (Concept) Meaning is also a concept that can be added to every concept.

With those two is possible to extract meaningful information. This structure might iterate over all requirements for an action, gathering meanings and making inferences.

NLU (well-known) challenges:

[yuripourre]

Interesting reading about NLU: https://thegradient.pub/machine-learning-wont-solve-the-natural-language-understanding-challenge/