## Add multi-slice support to HyperTree Grids

The "Slice" filter can now generate mutliple slices at once when the input is an HyperTree Grid.

Please note that this feature is not available when "Axis-Aligned" plane is selected
as cut function, since this option is deprecated in the "Slice" filter.
You can now use the dedicated "Axis-Aligned Slice" filter to do so.
