feat: SDK-1568 expose okhttp client as a configuration for XAP sdk

[dtayeh]

Situation

Some users of the SDK are interested in getting more control over the underlying httpClient used by the SDK, such as tuning the dispatcher concurrency configs, or injecting interceptors/eventlisteners for monitoring purposes

Task

Enable users to inject their own okhttp client when configuring the SDK client.

Action

• Client builder is modified into two builders, one with the shared configs, and another one extended with the timeouts configs.
• All existing base clients extend the Client.ConfigurableHttpBuilder to maintain current behaviour
• A new builder method that takes an okHttpClient as a configuration is added.
• Users can still configure timeouts on the default existing okhttp client

Testing

Manual testing by running the XAP examples covering test-cases:

• Configuring timeouts on XAP client
• Configuring a custom okHttpClient, user is unable to configure timeouts outside the httpclient.
• Configuring a client with the existing builder, users are able to set timeouts.

Results

Users are able to build and inject a custom okhttp client to be used by the SDK for executing requests.