[IMP] l10n_pe: enhance tax group and taxes for free billing support This commit enhances the tax group template in `account.tax.group.pe.csv` and he tax template in `account.tax.pe.csv` to support the free billin functionality by adding a dummy tax group. The related logic is implemented in the enterprise module. Related Enterprise PR: https://github.com/odoo/enterprise/pull/56767 closes odoo/odoo#174131 Related: odoo/enterprise#56767 Signed-off-by: Josse Colpaert (jco) <jco@odoo.com>