[DOCS] New tutorial sections

[AlexandreSajus]

Issue Description

Currently, the "Visuals" section has the tutorials "Long Running Callbacks" "Real-Time Data Visualization with Multithreading" and "Managing Multiple Users". The "Fundamentals" section has the tutorials "LLM Chatbot" and "RAG Chatbot".

These tutorials seem out of place and will, therefore, be hard to find.

Screenshots or Examples (if applicable)

Proposed Solution (optional)

I suggest moving them into new sections, such as "Backend" and "AI," respectively.

Code of Conduct

• [X] I have checked the existing issues.
• [X] I am willing to work on this issue (optional)

[FlorianJacta]

I need help understanding the part about backend and AI. Backend and AI don't mean anything to me and are very confusing with Taipy Core.

I agree with you about the place of the LLM tutorials

[jrobinAV]

Two remarks:

1. Taipy Core is progressively disappearing from the documentation. There is no need to be afraid of confusion about that. BTW, I would love the communication and sales teams to stop using the term core.
2. Backend means nothing to me either. 100% of Taipy applications, including pure visualization and dashboarding, are made with back-end features.

One general suggestion: For tutorials, I would try not to organize them by theme but more by the features covered by the tuto. I don't know how much it is applicable to our situation.

[FlorianJacta]

This was the goal for creating the different parts:

Big Data, Integration, Large Data

This is less true for Scenario Management and Visuals. We could come up with better divisions, but many of them are hard to classify, like Using Tables, Multi-page applications, Stylekit, etc.

They don't really fit a category of features.

[AlexandreSajus]

I still think we need a more generic word than Visuals. I am worried that people won't discover the invoke_long_callback tutorial independently since it is behind Visuals.

We seem to agree on creating an LLM section for the Chatbot and RAG tutorials though