cubicweb #2096328 Add ability to provide per-instance environment variables as config option [open]

In a similar way debian init scripts can have envvars set up in /etc/default/ files.

The use case I have in mind is vcreview, for which I'd like to set a HGRC environment variable so I can set up some specific mercurial configuration easily per instance.

This is an acceptable way to deal with the problem of configuring https access auth parameters, IMHO.

priorityimportant
typeenhancement
done in<not specified>
load0.200
load left0.200
closed by<not specified>