[MERGE] forward port branch saas-16 up to b3d0897f

...ount/static/src/js/reconciliation/reconciliation_model.js

addons/calendar/models/calendar.py

addons/calendar/tests/test_calendar.py

addons/hr_payroll/models/hr_payslip.py

addons/hr_payroll/models/hr_salary_rule.py

addons/sale/views/sale_views.xml

addons/web/static/tests/fields/relational_fields_tests.js

addons/website_slides/models/slides.py

doc/reference/guidelines.rst

odoo/addons/base/module/module.py

odoo/addons/base/module/wizard/base_language_install.py

odoo/modules/loading.py

odoo/service/db.py