Migrations good stuff (?)

- fine-grained crons (odoo days 2025 day 2 11B 1500 session "best practices to design odoo crons") https://youtu.be/nQKTKHUg4PA&t=6197 (18.0 / 19.0)
  - automated deactivation risk
  - process notification
- declarative constraints and indexes (19.0)
  -  how to migrate?
