[FIX] account: cash basis taxes: Make cash basis taxes work with the new tax report in any case.

Before that, since https://github.com/odoo/odoo/commit/71ee252dc43fd0e2b86ba8079c31915544e528eb , negative invoice lines were not supported by thoses taxes. Nor were miscellaneous entries. To make them work, we change the way tags are assigned to cash basis taxes : instead of copying them from the invoice, sign included, we now change their sign when appropriate, so that the resulting cash basis move can be treated like any regular miscellaneous operation by the tax report (so, always applying a factor of 1 to its lines' balance).

Doing that also allows us to re-simplify the code used in the tax report and tax audit computation to manage cash basis entries, and makes the cash basis entry more standard. This is also a usability improvement: now the user does not have to search for the original invoice to understand how the CABA entries are going to impact the report: it's always managed like a misc. operation, so he can just trust the signs of the tags.

v13 version of https://github.com/odoo/odoo/pull/53085



closes odoo/odoo#53503

Related: odoo/enterprise#11372
Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>