[12.x] feat: create UsePolicy attribute

[calebdw]

Hello!

This was bundled in #55765, but I'm splitting out into its own PR. Renamed from PolicedBy to UsePolicy.

#[UsePolicy(PostPolicy::class)]
class Post extends Model
{
}

Thanks!

[ahinkle]

Hi @calebdw 👋

What’s the use case here? Policy auto-discovery already works quite well, whereas the attributes of adding scopes or observers is pretty clear.

[calebdw]

@ahinkle,

The use case is to create an explicit connection between the model and policy instead of relying on magic naming conventions and placement (just like with UseFactory instead of just relying on the factory being in the right place).

[peterjthomson]

Our proposal for this was more complicated so UsePolicy makes perfect sense. We'll re-visit the cross-model policy mapping customisation and/or the closed-by default pattern in light of the new PR. Great to see Policies getting some love! https://github.com/icehouse-ventures/laravel-policy-attributes