The minimum required Python version is now stored as a variable in the codebase instead of being hardcoded. This makes it easier for developers to reference and manage Python version requirements, and helps determine when temporary code workarounds can be safely removed as Python versions are updated.

Make the mininum version of Python a variable so that it can be easily retrieved and used by the code. For example, it could be used to detect when a monkey patch should be removed.

Forward-Port-Of: odoo/odoo#163030
Forward-Port-Of: odoo/odoo#156774