[Tock Doc] Documentation for the New Structured Response System in the RAG Chain

[rkuffer]

This documentation explains the principles of the new prompting system, including a guide for configuring a bot. It is accompanied by three prompt examples illustrating different business use cases.

@zigzago @vsct-jburet :

As previously discussed, this modification to the RAG chain constitutes a breaking change for users of Tock’s integrated RAG. Existing prompts must be updated to comply with the structure described in the documentation. A warning should be added to the release notes, for example:

## ⚠️ Breaking Change — RAG Chain: Structured JSON Prompt Required
 
The RAG chain now expects the LLM to return a structured JSON object instead of a plain text string. **All existing Question Answering prompts in Gen AI > RAG Settings must be updated** before deploying this release, or the bot will fail to respond correctly.
 
See the [RAG Chain — Structured Prompt System](https://doc.tock.ai/tock/master/user/studio/gen-ai/rag-chain/rag-prompt-system.html) documentation for migration guidance and ready-to-use prompt templates.

NB: I hope I’ve correctly anticipated the URL for the doc once it’s published....

[zigzago]

LGTM. is the feature already on master @rkuffer ?

[rkuffer]

LGTM. is the feature already on master @rkuffer ?

Yes, this is the change introduced by this commit: e0dd199

[assouktim]

Thanks!