In the definition of periodic constraints, remove the assumption that all tasks have the same period
In the definition of periodic constraints, we assume for the moment that all tasks have the same period. For simplicity, for now we just propagate the period defined for one task to all tasks. This is not true in general (multi-rate scheduling) and should be generalized.
(from redmine: issue id 3757, created on 2019-07-02, closed on 2020-08-10)