After the rework of hr_homeworking, a traceback started occurring if the odoo
server was running in an environment with a different locale. Since
`.strftime("%A")` is a localized method, it wouldn't return the week name in
english. This would cause a traceback because we would try to access fields
that don't exist (e.g. jeudi_location_id). This commit changes the approach to
get the weekday number and uses an array to access the correct field name.
task-3570053
closes odoo/odoo#139736
Related: odoo/enterprise#49570
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>