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

it existed in previous versions

Those fields are similar to old odoo fiscalyear fields
Also added tests

(taken from the related account.move object)

- add new "end date" field (When this period ends)
- button "create monthly periods

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).