This commit improves a few methods related to the user profiles:
- Change _prepare_all_users_values so that it
works with a batch of users
- Change the _get_user_certificates and rename it to _get_users_certificates
so that it works with a batch of users to avoid doing a search in a
list comprehension.
This method will also be used to get the number of certificates per users
TaskID: 1952064
PR: #32229
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>