[doc] enhanced setup section: fix sections'level, more postgres tips, merge environment doc with cwconfig.py module docstring using custom autodocstring directive
#! /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