IFC4D code refactoring (#1834)

* P6XML Parser failing on calendar type

* add work plan references a get_person which is not an attribute. modified to get_user to work

* Initial support for Primavera XER files

* IFC4D impl XER calendars exceptions and work time

* merged updats

* refactoring code for the 4D model to avoid duplicate code

* Assign process in the api module was missing an atrribute QuantityIn Process

* Merged changes from master

* refactoring

* resolved conflicts

* refactoring code for IFC4D

* refactoring code for IFC4D

* refactoring code for IFC4D

* Reverted the changes to IfcRelAssignsToProcess usecase

* Changed the class to be more discriptive from Utils to ScheduleIfcGenerator

* reverted changes to add_work_plan and Makefile

Co-authored-by: Dion Moult <dion@thinkmoult.com>

src/ifcopenshell-python/ifcopenshell/api/sequence/assign_process.py

@@ -9,6 +9,7 @@ class Usecase:
             "relating_process": None,
             "related_object": None,
         }
+
         for key, value in settings.items():
             self.settings[key] = value