[pkg] Add new autopkgtest for skeleton packaging When running `cubicweb-ctl newcube`, the generated template provides debian packaging. So let's add automated tests for that using autopkgtest. The new test will generated a new cube, build a source tarball, build the package, try to install it, see if the Python 3 module is available and even run autopkgtest against the newly created packages. Along the way it will also print information about the generated package: buildinfo, package content, and lintian report.

Tests: unittest
Depends:
 python3-cubicweb, cubicweb-ctl,
 @builddeps@,
 python3-pytest,
 python3-flake8,
 python3-psycopg2, postgresql, postgresql-plpython,
 python3-ldap3, slapd, ldap-utils
Restrictions: allow-stderr, isolation-container

Tests: skeleton-packaging
Depends:
 python3-cubicweb, cubicweb-ctl,
 python3-pyramid, python3-wsgicors,
 devscripts, equivs, lintian, autopkgtest
Restrictions: allow-stderr, needs-root