[FIX] l10n_ar_afipws_fe: Parse proper format date from wsbfe webservice
[FIX] l10n_ar_afipws_fe: Parse proper format date from wsbfe webservice

Formerly was returing date in format 'DD/MM/YYYY', now we transform to
'YYYYMMDD' in order to be compatible when save info in Odoo

adhoc-dev/odoo-argentina,ingadhoc/odoo-argentina,adhoc-dev/odoo-argentina