feat: auth self-registration config + gql grouping

client/graph/admin/groups/groups-mutation-assign.gql

@@ -0,0 +1,12 @@
+mutation ($groupId: Int!, $userId: Int!) {
+  groups {
+    assignUser(groupId: $groupId, userId: $userId) {
+      responseResult {
+        succeeded
+        errorCode
+        slug
+        message
+      }
+    }
+  }
+}