- Arguments are now grouped in a new `PageData` NamedTuple, making it simpler to use, and
easier to extend.
- Page index is automatically calculated, and can be checked in callback to know which
page to show.
- Form send by calling entity is automatically parsed, using original form to instantiate
the right field types.
- A new `DataForm.get_field` method use Generic type as second argument to retrieve the
right field when getting a `submit` form.
- Updated all classes registering Ad-Hoc commands to use the new system and simplify the
code.
Pydantic models are now used for Ad-Hoc commands callback data. The `AdHocCommand` model
can (de)serialise the callback by using its import string.
This change has several benefits:
- better data validation.
- the serialisation mechanism will make communication with frontends easier.
- open the door for automatic documentation.
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