Add LLM configuration form while having a conversation

Problem/Motivation

1) Can be useful to change AI model when question difficulty changes.
2) Can be interesting to experiment with different settings.

Proposed resolution

Remaining tasks

1. Complete ✨ Rebase on AI module's abstraction layer Active
2. Implement form within conversation UI overriding default entity type settings.
3. Provide settings allowing admin to choose what controls to expose on conversation UI for the user.

User interface changes

API changes

Data model changes