feature: user flag assignment exporting

Disco.Services/Authorization/Roles/ClaimGroups/Configuration/UserFlag/UserFlagClaims.cs

@@ -11,6 +11,8 @@
 
         [ClaimDetails("Delete User Flags", "Can delete user flags")]
         public bool Delete { get; set; }
+        [ClaimDetails("Export User Flag Assignments", "Can export user flag assignments")]
+        public bool Export { get; set; }
 
         [ClaimDetails("Show User Flags", "Can show user flags")]
         public bool Show { get; set; }