PURPOSE Improve performance in often used views and fields in a normal Odoo usage. SPECIFICATIONS On res.partner model in website_crm_partner_assign, convert the computed field ``_compute_implemented_partner_count`` to use read_group. Performance test have shown it could be costly. Also rename ``implemented_count`` to ``implemented_partner_count`` to better match ``implemented_partner_ids`` naming. Task-2752043 Part-of: odoo/odoo#83806