## [REM] core: remove `name_get` API

### Rationale

Since v8, the `display_name` field is present on all models. By default, `display_name` uses `name_get` which has pretty much the same purpose (return record name used by the web client). Gradually, many (backend) developers (and the ORM: https://github.com/odoo/odoo/commit/6da1c3ac4c036eac289597602976538e243cb939) started using `display_name` (more convenient than `record.name_get()[0][1]`) but it still had the `name_get` override. It becomes more complex than necessary and poeple start to misunderstand the two (and sometimes override both, leading to inconstiencies between `display_name`/`name_get`).

To simplify the ORM and the API, we decided to keep only one of them, the `display_name` field:
- It is much more convenient from a backend point of view (`record.name_get()[0][1]` vs `record.display_name`)
- It is cached during the same transaction (and invalidated if its dependencies change)
- It can be overridden like any other compute field (override `_compute_display_name` with any extra dependencies)
- `name_get` is replaced by `read(['display_name'])` (API perceptive), which can actually be more efficient (if `display_name`'s depends are correct, the ORM will only fetch the fields it needs instead of every prefetchable field)

### Changes

- Deprecated `name_get` for the v17 and based the method on `display_name` (the opposite of before)
- Removed all usage of `name_get`
- Overrides of `name_get` are now overrides of `_compute_display_name`
- For `res.partner`, rename the field store `display_name` into `complete_name` because `display_name` context-dependent and it makes no sense to have a compute store that is context-dependent.
- Previously, it was possible to return multiple names for the same record with `name_get`, but it was tricky and most of the usage of this `name_get` didn't take this into account. The only example of this is the `name_get` of `product.product` (now use `", ".join(<names>)`).

## [IMP] core: fetch `display_name` during `name_search`

The `name_search` makes at least 2 SQL requests, one to find the records and one to read fields needed to compute the `display_name`. With the default `_compute_display_name`, it only needs to fetch the `_rec_name` field (if there is one), but the ORM perfetch field mechanism will also fetch every prefetchable field (see `_fetch_field`).

Then, to avoid running two queries and fetching too many fields, we add the dependency fields (with `_determine_fields_to_fetch`) to the select clause of the `Query` returned by `_name_search`.

## [IMP] *: add dependencies to `display_name` field

The previous commit introduced an optimization to reduce the number of queries and fields fetched when we call `name_search`. But it works much better when the dependencies of `display_name` contain field names used in the calculation (on the same record/model).

Then, to improve the performance and the cache coherency, add `depends` and `depends_context` depending on the custom `_compute_display_name`. Add only the first level of dependencies (never traverse relational field) because only these have a positive impact on the previous optimization and the cost is very low (see `modified`).

https://github.com/odoo/enterprise/pull/42599
https://github.com/odoo/upgrade/pull/4780
https://github.com/odoo/documentation/pull/4639