cubicweb-wireit #2493263 invalid media urls [validation pending]

Media should always use req.data_url(), not explicit "/data/..." url path; this is enforced be recent CW, leading to 404 errors on wireit media.

prioritynormal
typebug
done in0.2.0
load0.100
load left0.000
closed by#f209792a2db7 fix media url paths: usage of req.data_url is now enforced by CW (closes #2493263)