[FIX] l10n_at: supplement and fix tags + remove empty tax_ids

Cash flow tags were supplemented and useless and empty tax_ids removed.
Additionally account 7990 had a wrongly tag which was corrected.

closes odoo/odoo#80083

X-original-commit: 9de58fc6
Signed-off-by: Josse Colpaert <jco@openerp.com>