Add categories tracking

What does this MR do and why?

This MR introduces new action after we process a question from the user in chat. This action schedules another call to AI to ask AI to categorize questions into categories and then save those categories in the form of snowplow event.

things to follow up on:

• add rake task to regenerate XML file from CSV file
• add additional attributes defined in the issue

Related MR with Schema changes: https://gitlab.com/gitlab-org/iglu/-/merge_requests/94

Screenshots or screen recordings

How to set up and validate locally

1. ask chat a question
2. observe llm.log file to see that request to AI is sent
3. observe snowplow-micro

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #420261