feat: celero implementation

Author: yashasvi.kapil

backend/connector-integration/src/connectors.rs

@@ -91,3 +91,6 @@ pub use self::worldpay::Worldpay;
 
 pub mod worldpayvantiv;
 pub use self::worldpayvantiv::Worldpayvantiv;
+
+pub mod celero;
+pub use self::celero::Celero;