8.0 remove Purchase Requisition creation wizard

- Remove Button on Logistics Requisition Source to let those 2 options to create a Purchase Requisition:
  1. Standard way: 
      view: Logistics Requisition Line Form
      action: Button Create Purchase Requisition on Form
      Aim: Create a Single Purchase requisition for all Sources in Tender

  2. Advanced way:
     view: LR Source List
     action: More -> Create Purchase Requisition on Form
     Aim: Select precisely which Source you want in same Purchase Requisition

- Remove completely the code of the former Purchase Requisition Wizard
Here you do one `UPDATE` for each source where you could do one.
```
self.write({'po_requisition_id': purch_req.id})
```