Add a category property to DAGSet

[paulromano]

Short PR here adding a category property to the DAGSet class as well as adding a setter for the existing geom_dimension property.

[pshriwise]

The category and geom_dimension properties of the MOAB set are intrinsic to the class type. I'm wondering if class attributes would be better in this case.

class Volume(DAGSet):

    _geom_dimension = 3
    _category = 'Volume'

    @property
    def category(self):
        return self._category
    
    @property
    def dimension(self):
        return self._geom_dimension

    @classmethod
    def create(cls, model, volume_id=None):
        new_set = model.mb.create_meshset()
        self.model.mb.tag_set_data(model.category_tag, new_set, cls._catetory)
        self.model.mb.tag_set_data(model.category_tag, new_set, cls._geom_dimension)
        if volume_id is not None:
            ...

        return cls(model new_set)
      
    ...

We could then also add some checks in the __init__ method of the Volume, Surface, etc. classes to make sure that the handle passed in the constructor is tagged correctly to represent that class type.

[paulromano]

@pshriwise I just implemented your suggestion there. Right now, a mismatched geom_dimension or category will simply show a warning (note that this actually happens for groups in the fuel_pin.h5m file used in testing).

[pshriwise]

One more tiny request here, but then I think this is ready to go.

[pshriwise]

Thanks @paulromano!