Policies refactor, guest roles (#6732)

server/models/base/ParanoidModel.ts

@@ -8,6 +8,15 @@ class ParanoidModel<
 > extends IdModel<TModelAttributes, TCreationAttributes> {
   @DeletedAt
   deletedAt: Date | null;
+
+  /**
+   * Whether the model has been deleted.
+   *
+   * @returns True if the model has been deleted
+   */
+  get isDeleted() {
+    return !!this.deletedAt;
+  }
 }
 
 export default ParanoidModel;