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

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

@@ -0,0 +1,17 @@
+class Data:
+    products = {}
+
+    @classmethod
+    def purge(cls):
+        cls.products = {}
+
+    @classmethod
+    def load(cls, file, product_id):
+        if not file:
+            return
+        product = file.by_id(product_id)
+        cls.products[product_id] = {
+            "type": product.is_a(),
+            "PredefinedType": product.PredefinedType if hasattr(product, "PredefinedType") else None,
+            "ObjectType": product.ObjectType if hasattr(product, "ObjectType") else None
+        }