More Granular ACL Support in ModelView Beyond can_edit, etc.

[wnowicki]

Hi team 👋,

First off, thank you for the great work on this project — it's been a pleasure integrating it into my application!

I wanted to suggest a feature that I believe would be quite useful: enhanced Access Control Layer (ACL) support in ModelView, beyond the current simple flags like can_edit, can_create, and can_delete.

In my application, I've added a role field to my user model and implemented a bitwise representation of permissions. This allows me to define fine-grained access rules across different roles and actions. However, I'm now facing a challenge: there's no clear or extensible way to integrate these custom permissions into the existing ModelView logic.

Would love to hear your thoughts on whether this is something you'd consider, or if there's a recommended approach to achieve this kind of flexibility today.

Thanks again!

Wojtek