Draft: Independence from BIM (#17444)

* Draft: Independence from BIM - follow-up of #17390

* Draft: More info in DXF importer if BIM not present

src/Mod/Draft/draftobjects/shape2dview.py

@@ -230,7 +230,11 @@ class Shape2DView(DraftObject):
                         onlysolids = obj.Base.OnlySolids
                     if hasattr(obj,"OnlySolids"): # override base object
                         onlysolids = obj.OnlySolids
-                    import Arch
+                    try:
+                        import Arch
+                    except:
+                        print("Shape2DView: BIM not present, unable to recompute")
+                        return
                     objs = groups.get_group_contents(objs, walls=True)
                     if getattr(obj,"VisibleOnly",True):
                         objs = gui_utils.remove_hidden(objs)