[rql2sql] closes #1892473: enhance handling of optional inlined relation * some outer join aren't supported while they could * consider newly available 'optcomparisons' st information on variables (rql 0.30)

# copyright %(year)s %(author)s, all rights reserved.
# contact %(author-web-site)s -- mailto:%(author-email)s
#
%(long-license)s
"""%(distname)s views/forms/actions/components for web ui"""