[pkg] require python >= 3.4 This avoid pip pulling a version that does not run on python2 when using a python2 environment. Since we already released some 3.27 releases in pypi, I think we should release 3.27.3 and remove releases 3.27.2, 3.27.1 and 3.27.0 from pypi.

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