[IMP] sale,purchase,website: Harmonize the product name/description in reports and views

- sale: Improvement in quotation/so line's description
Currently, quotation/so line's description shows product's name with description.
It should show only description of product if description is there else show name of the product in backend views.

- sale: show product with description in sale report
Due to change in description of quotation/SO line, sale report is affected. Fixed it.

- website_sale: show only description in cart lines
Due to previous commit, cart lines shown with product and it's description as a quotation/so line's name.
When we create order from frontend, quotation/so lines' name field takes product name and it's description.
It should only take description if description is there else product name. Fixed it.

- purchase: Improvement in RFQ/PO line's description
Currently, RFQ/PO line's description shows product's name with description.
It should show only description of product if description is there else show name of the product in backend views.

- purchase: show product with description in purchase report
Due to change in description of RFQ/PO line, purchase reports are affected. Fixed it.