[datafeed] don't allow arbitrary kwargs on DatafeedParser initializer else they will be handled nicely by appobject base class, while we rather want an error in the case of a source parser (arguable).

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