[tableview] enhance RelationColRenderer. Closes #2093184
* subvid should only be explicitly specified, or default when main view (vid)
is known to support it (eg 'list' / 'csv')
* new is_rtype_view boolean flag to ease usage of view based on original
entity with a relation name and role, as the 'reledit' view for instance
debian/tmp/usr/bin/cubicweb-ctl usr/bin/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/cwctl.py usr/lib/PY_VERSION/site-packages/cubicweb
debian/cubicweb-ctl.bash_completion etc/bash_completion.d/cubicweb-ctl