[pkg] Replace custom "scripts" handling by a setuptools entry points
http://setuptools.readthedocs.io/en/latest/setuptools.html#automatic-script-creation
missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules)
embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js