Remove the useless nullslastquery.py file since its code is doing nothing
This file define a custom QueryManager whose whole purpose is to change the ordering of the null elements... but the code does in fact nothing since the method get_ordering()
that contains the whole logic of it... does not exist in django since 1.8 in 2015 !!!!!
The whole thing is doing nothing ! Does the ordering has a problem or not ? If not get rid of this pile of