Automated actions can now react to more business events, including record deletion and form changes, and can use previous field values when records are updated. This gives teams more control over workflows and helps ensure rules stay reliable when changed.

Contributions from @tgr-odoo :
- add old values in context when evaluating an action upon a write;
- allow automated actions to be triggered on deletion of records;
- allow automated actions to be triggered on form change.

Extra contribution from @rco-odoo:
- when modifying action rules, force the registry to reload

On-write automated actions now receive the record's previous values in their context. This lets businesses create more accurate automation that reacts to what changed, not just the final result.

When triggering an on write automated action, put the old values in the context so they're accessible from the server actions

Businesses can now set automated actions to trigger when a record is about to be deleted. This helps teams automate cleanup, notifications, or checks before information is removed from the system.

These changes allow to trigger automated actions on deletion of a record
The server actions are run _before_ the record is deleted

Odoo now supports creating custom temporary models, which are useful for short-lived workflows and wizard-style interactions. The change also protects key model settings from unsafe edits and requires a small database update for existing installations.

SaaS customizations can now create temporary custom models when needed. This gives administrators more flexibility for short-lived data structures without changing permanent business data models.

This PR allows to create transient custom models in SaaS customization
- Adds a boolean field 'create_transient_model' in ir_model model
- Instantiates a TransientModel instead of Model in registry if create_transient_model is True