Add instructions to setup new triage ops pipeline

Migrated changes over from gitlab-com/www-gitlab-com!26333 (closed)

I incorporated the feedback from the original MR into this documentation. I prefer this in the README over a docs folder for now since there's not a lot of information currently captured within the repo. I know there is broader documentation needs and this can be pulled out later.

I'm working on other learning items with the GDK, GitLab QA and a few other items so no need for quick feedback @godfat @rymai @markglenfletcher

Closes #209 (closed)