feat(connector): add support for external authentication for cybersource (#4714)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>
Files to modify:


**enums.rs**
  Modify existing code

**authentication.rs**
  Modify existing code

**schema.rs**
  Modify existing code

**router_request_types.rs**
  Modify existing code

**router_response_types.rs**
  Modify existing code

**transformers.rs**
  Modify existing code

**cybersource.rs**
  Modify existing code

**transformers.rs**
  Modify existing code

**transformers.rs**
  Modify existing code

**transformers.rs**
  Modify existing code

**transformers.rs**
  Modify existing code

**utils.rs**
  Modify existing code

**types.rs**
  Modify existing code

**authentication.rs**
  Modify existing code