[IMP] sale_crm: on opportunity form view, add a button linking to the
sales related to the current opportunity, using a stat button. Two fields are
introduced: opportunity_id on sale.order (automatically set when using the
make sale wizard), and sale_amount_total on the opportunity, function field
computing the total amount for the not canceled quotations related to the
opportunity.
[IMP] share: now restricted to the technical group, as this is a very
tricky feature. Also changed the order in the more menu.