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

src/ifcopenshell-python/ifcopenshell/api/grid/create_grid_axis.py

@@ -0,0 +1,21 @@
+class Usecase:
+    def __init__(self, file, settings=None):
+        self.file = file
+        self.settings = {
+            "AxisTag": "A",
+            "SameSense": True,
+            "UVWAxes": "UAxes",  # Choose which axes
+            "Grid": None,
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        element = self.file.create_entity("IfcGridAxis", **{
+            "AxisTag": self.settings["AxisTag"],
+            "SameSense": self.settings["SameSense"]
+        })
+        axes = list(getattr(self.settings["Grid"], self.settings["UVWAxes"]) or [])
+        axes.append(element)
+        setattr(self.settings["Grid"], self.settings["UVWAxes"], axes)
+        return element