MOC order for spatial filters could lead to inefficient parquet filters

Currently we determine the MOC order for spatial filters by using the Pixel Tree, since initially the only purpose of the filter MOCs were to filter the pixel tree in the coarse filtering stage. However we now use the filter MOCs to generate pyarrow filters, and this could lead to inefficient filtering. The filtering MOC order could be generated instead from the catalog MOC order or the filter size to make it more efficient.