Allow admin to print a posted/paid invoice without using cache to refresh some data's
Following https://discuss.tryton.org/t/strategy-to-generate-a-new-version-of-the-invoice-report/5596/1 Sometimes customer request to update some data's not involved in accounting on a posted invoice (name, address,...). Until now, Tryton stores a copy of the binary invoice report to keep the original values readonly.
In some countries, it's not allowed to modify such document so only admin user is allowed for this task.
With this feature, admin user will be allowed through a wizard to print an invoice without using the report cache. This way, some data's could be updated on the report. The previous report will be stored in a new model InvoiceCache which will store all printing revisions. This way, the user could easily goi back to a previous report.