[tests/repository] use the new connection api (part 2/2) Some notes: * module imports cleanup * the unimplemented `test_transaction_interleaved` is wiped

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