RFC: management of librarian permissions on acquisition module

We would want to follow for the Acquisition module the same logic as implemented for the Tools module to have more granular permissions than at present.

Permissions could be:

• budget_create_new : permission to create a new budget
• budget_allocate : permission to allocate an amount to a budget, either during the process of creating the budget, or afterwards
• budget_invoice : permission to create an invoice on a given budget, i.e. debit the budget
• budget_encumbrance : permission to commit any amount to an order
• basket_create : permission to create an order basket
• basket_close : permission to close an order basket
• suggestion_acceptorreject : permission to accept/reject/delete suggestions
• vendor_createoredit : permission to create/edit/delete a vendor
• order_claim : permission to claim late orders