feat: Add connection serializer

packages/backend/src/serializers/connection.js

@@ -0,0 +1,16 @@
+const connectionSerializer = (connection) => {
+  return {
+    id: connection.id,
+    key: connection.key,
+    reconnectable: connection.reconnectable,
+    appAuthClientId: connection.appAuthClientId,
+    formattedData: {
+      screenName: connection.formattedData.screenName,
+    },
+    verified: connection.verified,
+    createdAt: connection.createdAt.getTime(),
+    updatedAt: connection.updatedAt.getTime(),
+  };
+};
+
+export default connectionSerializer;