DMN module exposes API to evaluate decisions

[saig0]

Description

Extend the DMN module to evaluate DMN decisions.

• expose the API evaluateDecisionById(parsedDecision, decisionId, context): EvaluationResult
  • context allows to access variables
  • EvaluationResult contains the result of the decision evaluation
  • EvaluationResult contains the failure message if the evaluation failed
• create a context object for the access of variables from the decision
  • goal: allows to access a variable by its name
  • but the DMN engine doesn't support a context yet - only plain variables as Map[String, Any]
  • workaround: load all variables from the state
  • next steps: extend the DMN engine and update the context access

blocked by #8063
blocked by #8081