Included classify_completeness function

This MR includes the classification of completeness function based on the built_up_ratio.

\approve @fd @cnievas

As in 275, I set all >= 0.25 to complete with a value of 1 and incomplete with a value of 0, is this fine or should I pick other integers for it (i.e. negative values or the ones for complete and incomplete from the clickpleteness)?