[IMP] sale: allow to show total of order line tax inc or based on unit price.

Allow to set in configuration mode b2b or b2c.
Change the column of order line in sale view and in reports depending of sale.

Fix price_reduce field (wrong if tax was included in price)
and merge with code discounted_price from website_sale.

Change header from reports "Price Tax Excluded' by 'Price' in report.
That is wrong, sometime the amount can haxe tax included in the price.