[devtools] Adjust skeleton setup.py to have it read information from __pkginfo__.py Since the later is now installed in cubicweb_<CUBENAME> directory. Add a test ensuring that `python setup.py sdist` works on newly created cube (which should at least verify that setup.py is valid). Related to #13001466.

etc/init.d
etc/cubicweb.d
etc/bash_completion.d
usr/bin
usr/share/doc/cubicweb-ctl
var/log/cubicweb
var/lib/cubicweb/backup
var/lib/cubicweb/instances