[web] allow configuration of the Content-disposition value The `set_content_type` function now takes and optional `disposition` parameter to control the value of this HTTP header. Use of `Content-disposition: inline` with a filename parameter are valid, so the presence of filename does not allows to choose between `attachment` and `inline`

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