[pkg] Run test suite as part of autopkgtest
Add support for autopkgtest. The test “unittest” will run the test
suite using pytest. As we need PostgreSQL in the test environment
and open network connection, the test is marked with
`isolation-container` and requires at least LXC to be run, e.g:
autopkgtest -s -- lxc -s autopkgtest-sid
etc/init.d
etc/cubicweb.d
etc/bash_completion.d
usr/bin
usr/share/doc/cubicweb-ctl
var/log/cubicweb
var/lib/cubicweb/backup
var/lib/cubicweb/instances