rate limits on prelogin

src/Api/appsettings.json

@@ -218,6 +218,11 @@
         "Endpoint": "post:/organizations/*/users/*/reinvite",
         "Period": "1d",
         "Limit": 300
+      },
+      {
+        "Endpoint": "post:/accounts/prelogin",
+        "Period": "1m",
+        "Limit": 10
       }
     ]
   },