Path: Allow parent job assignment

Modifications focus on allowing the creation of operations to include direct provision of parent job.
Path: Remove `useGui` implementation

src/Mod/Path/PathScripts/PathThreadMilling.py

@@ -327,11 +327,11 @@ def SetupProperties():
     return setup
 
 
-def Create(name, obj=None):
+def Create(name, obj=None, parentJob=None):
     '''Create(name) ... Creates and returns a thread milling operation.'''
     if obj is None:
         obj = FreeCAD.ActiveDocument.addObject("Path::FeaturePython", name)
-    obj.Proxy = ObjectThreadMilling(obj, name)
+    obj.Proxy = ObjectThreadMilling(obj, name, parentJob)
     if obj.Proxy:
         obj.Proxy.findAllHoles(obj)
     return obj