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

src/ifcopenshell-python/ifcopenshell/api/spatial/remove_container.py

@@ -0,0 +1,20 @@
+import ifcopenshell
+
+
+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):
+        contained_in_structure = self.settings["product"].ContainedInStructure
+
+        if contained_in_structure:
+            related_elements = list(contained_in_structure[0].RelatedElements)
+            related_elements.remove(self.settings["product"])
+            if related_elements:
+                contained_in_structure[0].RelatedElements = related_elements
+            else:
+                self.file.remove(contained_in_structure)