[IMP] sale: show complete SO view by default

Instead of showing the columns delivered/invoiced qties on SOs
by setting a special key in the view's context, let's do the opposite
and hide them for a sepcial key instead.

The rationale behind this decision is that when a user wants to see
a SO from another place in the system, it is often a SO and not a quote
(i.e. accessing from an invoice's chatter message, from a subscription,
etc.). The default should then be to show these fields unless otherwise
specified in the context (and not the opposite).