feat: add user roles and storage quota management

libertas_core/src/authz.rs

@@ -0,0 +1,25 @@
+use uuid::Uuid;
+
+use crate::models::{Album, Media, Role, User};
+
+pub trait Ownable {
+    fn owner_id(&self) -> Uuid;
+}
+impl Ownable for Media {
+    fn owner_id(&self) -> Uuid {
+        self.owner_id
+    }
+}
+impl Ownable for Album {
+    fn owner_id(&self) -> Uuid {
+        self.owner_id
+    }
+}
+
+pub fn is_admin(user: &User) -> bool {
+    user.role == Role::Admin
+}
+
+pub fn is_owner(user_id: Uuid, entity: &impl Ownable) -> bool {
+    user_id == entity.owner_id()
+}