GitHub Apps and User RBAC have full access to enterprise settings, and all new features will support granular permissions [GA]

### Value Prop

Every Enterprise-level features will support the fine-grained permissions model, for both user roles and GitHub App installations. The result is that enterprise administrators can delegate their work safely to other users in their enterprise or GitHub Apps for automation.

More importantly, GitHub will not allow new enterprise features to ship without support for these platforms, where relevant. All new APIs will support GitHub Apps and fine-grained PATs, and all new enterprise features will be delegatable via custom roles.

### Expected Outcome

Enterprises can use the granular authorization model for Apps and roles with confidence, knowing that future features won't require a regression to less secure patterns.