Create backend for AI chat user interface

Moving issue to another module https://www.drupal.org/project/openai_assistants →

Hi @mindaugasd while I agree that collaboration on common components is a good approach, I'm concerned that aichat is at an Alpha stage, so a lot of the organisations that could potentially use openai_assistants might avoid it as part of a policy of not using Alphas on production projects.

For now the UI is done on this module and I'm going to focus on other items on the roadmap, but will be happy to revisit the UI later on once other features are completed.

policy of not using Alphas on production projects.

alpha stage is quite common in Drupal, at least historically for many projects, while also projects grow to be popular while remaining in alpha stage.
At the same time, adding aichat backend does not require to create a dependency. Organizations can use openai_assistants without using aichat, but having aichat as an additional option to try, which does not impact stability in any way.

focus on other items on the roadmap, but will be happy to revisit the UI later on once other features are completed.

Ok, whenever it will seem like a worthwhile path to start exploring.