Model-bakery

Added
- Add Django 5.1 support

Changed
- Fix support of `GenericForeignKey` fields in combination with `_fill_optional`

Changed
- Fix `make_recipe` to work with `_quantity` (28)

Changed
- Replace expensive `count()` with cheap `exists()`

Added
- Add Django 5.0 support

Changed
- Allow baking without `contenttypes` framework

Removed
- Drop Django 3.2 and 4.1 support (reached end of life)

Added
- Add support to `auto_now` and `auto_now_add` fields.

Changed
- Remove unnecessary casting to string methods `random_gen.gen_slug` and `random_gen.gen_string`
- [doc] Update installation command