It happen that a company has to trigger the invoicing action to generate invoices before
the scheduled date (to print and prepare invoices documents, check invoices, etc.).
This requires technical access for end users with the risk that this represents.
This commit adds a new wizard to run the invoicing action for a given date with a helper
to see and check the contract that will be invoiced. When the manual action is called,
the system displays all created invoices.