[FIX] point_of_sale: ACLs for pos users

POS users should not be able to create nor modify payment methods (account.journal)
POS users should not be able to create nor modify point of sales (pos.config)

At first opened session, if no payment methods was set, this is possible that the pos user should temporary have accesses granted to mark a payment method as pos payment method. This is done by the openerp.SUPERUSER_ID added by this rev.

opw-625489