Remove OpenAI SDK dependency and extend it from Drupal AI core module

Thanks Artem to take a look on this!

If it doesn't have specific logic, them I would say that we can just remove it and take the logic form base class.

Its acutally not working at the moment, because the loading of the client doesn't work. I added some comments, outside of that I see that we can remove:

chat
isUsable
getConfig (if we do https://www.drupal.org/project/ai/issues/3535963 📌 Use $this->pluginDefinition['provider'] for getConfig Active )
getApiDefinition (if we do https://www.drupal.org/project/ai/issues/3535963 📌 Use $this->pluginDefinition['provider'] for getConfig Active )

I have tested logging, chat with streamed response, normal chat. Everything works now and now it is so easy to maintain and expand the functionality, as all OpenAI based providers will get the updates directly from AI Core.

MR is approved.

Merged. All is green in the pipeline