Remove unnecessary conditions related to invoices

in account.move model

This commit consolidates the logic for updating date fields in the
`account.move` model into a single private method `_update_dates`.

Docstrings

obsoleted by accounting date this module adds.

To be reworked.

or an accounting document.
Updated the translations.

Specifics to play better with accounting changes:

* No longer change the base ``date`` field; add ``accounting_date`` instead.
* Build periods when loading accounting data for a new company.

The copy of a transaction_date should be disabled by default.

Updated the translations.
Updated the unit tests.

Note that when the account move date is empty an exception:
constraint null value is raised during execution of action_move_create() method.

Add force_period_on_date context to always make the period be around the current date.

Note that we send a accounting date in reverse_moves func and
the fill_acocunting_date should use it instead of today date.

Updated the translations.
Executed "black" and "isort".

Simplify the code in the process to iterate on each accdoc one at a time (as we
now have a behavior (cut-off) that depends on journal types).