Implement autocomplete API endpoints

The documentation for this can be found here.

https://support.travelpayouts.com/hc/en-us/articles/360002322572-Autocomplete-API-for-countries-cities-and-airports

Review the linked TravelPayouts Autocomplete API documentation to understand the required endpoints and data structures. Examine the existing SDK code to see how other API endpoints are implemented, likely in a client class. Create new methods for the autocomplete endpoints, ensuring they handle parameters and return responses consistently with the rest of the SDK. Test the implementation by making requests to the live API.

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