Notify failed master pipeline status in merge requests if the merge request can potentially be blocked by the same failures

Proposal

Suggested in #419 (comment 1806203314)

create a new triage-ops processor that would act when a pipeline finishes, to update the latest status of each job (we should also store the finished_at of jobs in the JSON status file) so that we only update the status if finished_at is > existing_status finished_at

Context

we would like to capture the statuses of gitlab master pipeline jobs in a status page, and use this information to decide if a full pipeline after MR approval should run, or cancel if a full pipeline is triggered.

Action Plan

• Create a master pipeline jobs status page. status page is now live
• Allow triage-ops to update the status page by reacting to succeeded/failed master pipelines. See MR
• With Danger, alert MR if pipeline is likely blocked by a broken master pipeline. See MR
• (Optional, depending on feedback) update the new_pipeline_on_approval processor to check the status page before triggering pipeline.
• (Optional, depending on feedback) fail the Danger job added in step 3 when a master pipeline failure is detected, and when the chance of it being flaky is slow (for example, if the failure did not happen in an rspec test)