Added support for OpenAI Moderation

[ricken07]

The OpenAI Moderation is a tool you can use to check whether text is potentially harmful.

This PR content :

• Moderation API
• Moderation Client
• Moderation properties
• Test

[tzolov]

@ricken07 if not mistaken there is already a similar PR : #333 by @hemeda3
The moderation is has high priority in our todo list. But we need to figure out what high level abstraction to provide that can be used across the various models.

[ThomasVitale]

The OpenAI implementation of the ModerationModel interface has been delivered in 1894681

Documentation: https://docs.spring.io/spring-ai/reference/api/moderation/openai-moderation.html

I think this issue can be closed now.

[markpollack]

Closing, sorry for the cross talk/overlap between PRs. Hope to avoid this in the future by staying more on top of the PRs.