8.0 port sale condition text

 	port sale_condition_template …

* rename account.condition_text to base.condition_template
* move fields in view to reflect document print
* rename type of field to position
* give better position names
* split module to be able to reuse conditions for purchase condition (used in https://github.com/OCA/purchase-reporting/tree/8.0/purchase_order_webkit_with_notes)