Expose client configuration through api factory

[fgoncalves]

In our code base we found it very useful to expose the ClientConfiguration through the ApiClientFactory. This let's us for example set the user agent for all our calls since we do a lot of client identification based on this header.

We'd like to propose this change. We didn't break the contract and respected the method chaining previously there. One can set the configuration as such:

new ApiClientFactory()
                .clientConfiguration(clientConfiguration)
                .endpoint("some endpoint");

Thank you

[AutomatedPlayground]

+:b:

[laurens]

+1 thanks!

[fosterzhang]

Make sense. Thank you.