[router] add router db connector for responses api (#10487)

sgl-router/src/data_connector/mod.rs

@@ -0,0 +1,11 @@
+// Data connector module for response storage
+pub mod response_memory_store;
+pub mod response_noop_store;
+pub mod responses;
+
+pub use response_memory_store::MemoryResponseStorage;
+pub use response_noop_store::NoOpResponseStorage;
+pub use responses::{
+    ResponseChain, ResponseId, ResponseStorage, ResponseStorageError, SharedResponseStorage,
+    StoredResponse,
+};