Add global constraint that prevents property changes

[aljoshakoecher]

The fact that we are building the planner for plug & produce scenarios means that we need a global constraint that prevents properties from being changed at will.
In normal planners (e.g. the classic SMTPlan approach), it is assumed that all actions are defined and the properties “match” the actions.
However, in our system, one could also model required capabilities that use properties that do not currently appear in the provided capabilities, e.g., because no suitable provided capability is yet available.

In such cases, the planner currently finds the trivial solution (no capability, but planning problem can be satisfied), because the properties can simply change without a capability application. The corresponding constraint is missing because it is only inserted with a provided cap.

Solution:
Introduce a global constraint stating that properties can only change when a (any) capability is executed.