[web application] move default path logic inside url publisher
Previously, this logic was handle by:
* etwist server
* wsgi handler
* web application
#! /bin/sh -e#if [ "$1" = configure ]; then if which install-docs >/dev/null 2>&1; then install-docs -i /usr/share/doc-base/cubicweb-doc fifi#DEBHELPER#exit 0