Bug 24157: New permission - edit_invoices

Bug 24157: New permission - edit_invoices

Add a new permission to edit invoices

Test plan:
- Remove the new permission "edit_invoices" for a given patron,
use it to log in into Koha
- Create an invoice, edit it (click "detail")
=> You can see the detail of the invoice, but cannot edit it. It's a read-only view.
- Add the permission
=> The form is back and you can modify the invoices and save the changes.
Also, you are able to create adjustments.

Sponsored-by: Galway-Mayo Institute of Technology
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Alex Arnaud <alex.arnaud@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>