feat: add OkHttp transport module

[Mohammad-Dwairi]

Situation

One of the features of the new core module is its flexibility in supporting diverse HTTP clients by allowing end-users or product SDKs to inject their preferred implementations. This is achieved by implementing the Transport interface for synchronous requests or the AsyncTransport interface for asynchronous requests.

To achieve full decoupling between the core module and any specific HTTP client library; we will publish packages that integrates different HTTP clients (e.g., OkHttp, Apache HTTP) with the SDK's Transport interfaces. SDK users simply need to include dependencies on both the product SDK and one of the supported HTTP client packages.

In this PR, we are introducing a new module expediagroup-sdk-okhttp-transport that offers a ready-to-use Transport implementation using OkHttp.

Caution

Changes in this PR are already on the main branch and has been reviewed earlier. This PR extracts all OkHttp-related files to a new module.

Task

Move all OkHttp related files to a separate module.

Action

1. Initialized a new module expediagroup-sdk-okhttp-transport
2. Copied the classes and files from okhttp package to the new module.

Testing

1. All tests are passing.