Purpose of this commit is to give description more "business oriented"
because those descriptions appears in Odoo Studio which is supposed to be used by end users, not only by developers.
Related Task ID : 37311
Let `create` and `write` round monetary field values before sending them to the
database. Pass the values to be written to `field.convert_to_column`, so that
the currency can be retrieved from the values, and the value be rounded.
Simplify the API as much as possible, and delegate all the implementation
details to the models `ir.model`, `ir.model.fields`, `ir.model.constraint` and
`ir.model.relation`.
This removal has led to a necessary refactoring:
- make the setup of field attributes extensible;
- make the instantiation of custom fields extensible;
- delegate model and field reflection to `ir.model` and `ir.model.fields`;
- move the implementation of sparse and serialized fields to module `base_sparse_field`;