as noted in https://github.com/FreeCAD/FreeCAD/pull/4271#discussion_r554673632 the pointer to the UI should be a unique pointer. This PR does this for all TD dialogs that don't already use a unique_ptr.
as discussed in the forum, the hatch feature misses a dialog. So here it is. The code is more or less just the one of the existing GeomHatch dialog