[debian] Update debian packaging (closes #16133259)
- use dh_python, pybuild and debhelper>=9,
- refactor and simplify the debian/rules,
- rename binary packages (but cubicweb-ctl) to python-xxx
- remove daemon handling stuff (initscripts...) from cubicweb-ctl (one should
now use a standard WSGI delivery method),
usr/lib/python2*/*-packages/cubicweb/devtools/
usr/lib/python2*/*-packages/cubicweb/skeleton/
usr/lib/python2*/*-packages/cubicweb/test
usr/lib/python2*/*-packages/cubicweb/dataimport/test
usr/lib/python2*/*-packages/cubicweb/entities/test
usr/lib/python2*/*-packages/cubicweb/ext/test
usr/lib/python2*/*-packages/cubicweb/server/test
usr/lib/python2*/*-packages/cubicweb/sobjects/test
usr/lib/python2*/*-packages/cubicweb/hooks/test
usr/lib/python2*/*-packages/cubicweb/web/test
usr/lib/python2*/*-packages/cubicweb/etwist/test