Global push/pull rules are error prone and can be replaced efficiently
by creating a "global" route.
There was an odd behavior when you delete a route, the different rules
of this route were'nt deleted and thus became global. A lot of users
didn't understand that, so to avoid this unexpected behaviour, we
delete on cascade the push and pull rules when a route is deleted.
To avoid inconsistencies in the system, we also restrict the deletion of
rules when they are used in a stock move or in a procurement. We also
restrict the deletion of routes used in warhouses and order lines.
We change the global pull rule test by applying the procurement rule on
a route and apply this route on a product.
Menu items related to global rules are removed, so are the logic to look
for them in the methods looking for which pull/push rule to apply.
joint work by @dpa-odoo, @pimodoo and @sle-odoo