Create incidents for review-deploy failed jobs

Context

• Closes gitlab-org/quality/engineering-productivity/team#154 (closed)
• Closes #379138 (closed)

What does this MR do and why?

• When the review-deploy fails in any pipeline, we'll run the review-deploy-failure-notification job, which will do two things:
  • Create an issue in https://gitlab.com/gitlab-org/quality/engineering-productivity/review-apps-broken-incidents
  • Send a slack notification in #review-apps-broken

This MR contains additional goodies:

• I created specs for generate-failed-pipeline-slack-message.rb
• I've also "fixed" a small issue in generate-failed-pipeline-slack-message.rb, where we relied on the BROKEN_BRANCH_INCIDENTS_PROJECT env variable in the code. We now need to pass it explicitly with the -p flag.

Side activities I did for this MR to work

• I created a new project: https://gitlab.com/gitlab-org/quality/engineering-productivity/review-apps-broken-incidents
• I created an project access token called BROKEN_REVIEW_APPS_INCIDENTS_PROJECT_TOKEN, and added it in the gitlab-org/gitlab CI/CD variables
• I've created a ~review-app-broken label in https://gitlab.com/gitlab-org/quality/engineering-productivity/review-apps-broken-incidents

Screenshots or screen recordings

• See an example issue: gitlab-org/quality/engineering-productivity/review-apps-broken-incidents#2 (closed)!
• See an example slack notification (internal link):

How to set up and validate locally

TBD

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.