feat: add custom segment param for flight listings

[anssari1]

Situation

GetFlightListingsOperationParams has segment params, for which each piece of detail is passed separately.

GetFlightListingsOperationParams
   .builder()
   .segment1Origin()
   .segment1Destination()
   .segment1DepartureDate()
   .segment2Origin()
   .segment2Destination()
   .segment2DepartureDate()
   .build()

Task

Add a new custom segment data class to hold the details of a segment and pass it to the builder of GetFlightListingsOperationParams

Action

Parse GetFlightListingsOperationParams, and introduce the custom code into it

Testing

Generated an SDK with new customization applied, and tested it manually

GetFlightListingsOperationParams
   .builder()
   .segment1(Segment.builder().origin().destination().departureDate().build())
   .segment2(Segment.builder().origin().destination().departureDate().build())
   .build()