[FIX] base: Malaysian currency

Default Currency for Malaysia is MYR (Malaysian ringgit), not MXN (Mexican peso)
Fixes #4193
[FIX] sale_margin: margin handle included taxes for sale

Another fix should probably be build for purchase price, but it isn't that easy, we need to know the partner to which the product has been purchased, as taxes are partner/country dependent.

Besides, included taxes in purchase prices happen less often.