Implement task-based parametric cost item quantities

src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py

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+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"cost_item": None, "products": []}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        self.quantities = set(self.settings["cost_item"].CostQuantities or [])
+        for quantity in self.settings["cost_item"].CostQuantities or []:
+            for inverse in self.file.get_inverse(quantity):
+                if not inverse.is_a("IfcElementQuantity"):
+                    continue
+                for rel in inverse.DefinesOccurrence or []:
+                    for related_object in rel.RelatedObjects:
+                        if related_object in self.settings["products"]:
+                            self.quantities.remove(quantity)
+        self.settings["cost_item"].CostQuantities = list(self.quantities)
+
+        for product in self.settings["products"]:
+            ifcopenshell.api.run(
+                "control.unassign_control",
+                self.file,
+                related_object=product,
+                relating_control=self.settings["cost_item"],
+            )