feat: Sync user experience SLIs job

A new job to:

1. Sync User Experience SLIs
2. Run make generate
3. Open a new MR with the changes.

The trigger will be a scheduled pipeline that lives in https://gitlab.com/gitlab-com/gl-infra/observability/team.

Originally, this script was supposed to be part of the Observability tracker, but it doesn't have all the dependencies that runbooks has for generating the recording rules. I did a quick attempt of running make generate from there, but it failed, and I thought it wouldn't be worth investing time trying to make it work from there. The simpler alternative is to keep the job that runs the script in runbooks, and implement the scheduled pipeline to trigger this job in the Observability tracker.

Here is the MR created by this change !10513 (merged) (ran locally by myself to test)