[pkg] Drop NO_SETUPTOOLS option
setuptools is the defacto standard nowadays. The only place where
NO_SETUPTOOLS option was used is during packaging (RPM, Debian) and even in
this context, it seems that setuptools is the way to go
(see https://wiki.debian.org/Python/LibraryStyleGuide).
version=3
opts=uversionmangle=s/(rc|a|b|c)/~$1/ \
https://pypi.debian.net/cubicweb/cubicweb-(.+)\.(?:zip|tgz|tbz|txz|(?:tar\.(?:gz|bz2|xz)))