First attempt at ripping out agnostic code into ifcopenshell.api namespace. See #1399.

src/ifcopenshell-python/ifcopenshell/api/root/remove_product.py

@@ -0,0 +1,27 @@
+import ifcopenshell.api.geometry.unassign_representation as unassign_representation
+import ifcopenshell.api.geometry.remove_representation as remove_representation
+
+
+class Usecase:
+    def __init__(self, file, settings=None):
+        self.file = file
+        self.settings = {"product": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        representations = []
+        if self.settings["product"].is_a("IfcProduct"):
+            if self.settings["product"].Representation:
+                representations = self.settings["product"].Representation.Representations or []
+            else:
+                representations = []
+        elif self.settings["product"].is_a("IfcTypeProduct"):
+            representations = [rm.MappedRepresentation for rm in self.settings["product"].RepresentationMaps or []]
+        for representation in representations:
+            unassign_representation.Usecase(
+                self.file, {"product": self.settings["product"], "representation": representation}
+            ).execute()
+            remove_representation.Usecase(self.file, {"representation": representation}).execute()
+        # TODO: remove object placement and other relationships
+        self.file.remove(self.settings["product"])