[test] Update webconfig's tests accounting for cubicweb-file being now a package WebconfigTC.test_locate_all_files and WebconfigTC.test_locate_resource assumed that cubicweb-file was installed in <share>/cubes/file whereas, from the latest release, it is now a standard Python package thus installed in site-packages as cubicweb_file. We simply update base directory of these two tests.

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