Accounting Periods

Per-period accounting concept. Periods can be individually closed. Periods are filled based on an accounting date this module adds which users may however set in advance.

Dates reworked in accounting documents / invoices:

• Add accounting date used to select the right period.
• Add transaction date.
• Hide default date field, obsoleted by accounting date above.

Inspired from what used to be available in previous Odoo versions.