Refine "has_external_id" to "has_parliament_id" and "has_governement_id'

In most if not all cases in Europe, the legislative process will have an ID at the parliament and an ID at the governement/executive. Our property "has_external_id" could be refined with 2 subproperties to explicitely state which is the ID at the parliament and which is the ID at the governement.

Source : alignement JoLux - ELI-DL