decision_points: Add proof of concept for a cross-diagram mavo menu
decision_points: Add decisions and alternatives to the z3 encoding

 * Add functions for alternatives
 * Add constraint for elements in an alternative
 * Add decision constraints
 * Fix mayOnly not overridable through input properties
 * Fix model types inheriting from the wrong mavo uri
decision_points: Fix wrong usage of xors in alternative encoding
Merge branch 'decision_points' (checkpoint mavo alternatives encoding)
mavo: Fix function name referring to old formulaIds