Show jobs in context of pipeline
Description
When looking at a build, we currently render related builds in a horizontal, wrapping list. After #18516 (closed), we'll compress that build list a bit, and group them by stage. After #18141 (closed), we'll have a pipeline graph of all builds and stages in the pipeline.
When transitioning from a pipeline to a build, it's a bit jarring. You lose the pipeline graph, which kind of acts as a map. You can quickly navigate to other builds in the pipeline, but wouldn't it be better to use the pipeline graph as a navigation map? Also, there's meta and ambient information about the pipeline that is lost. From purely an IA perspective, it's a bit weird to navigate to peer-level items rather than treating the pipeline like a parent of the build. Lastly, from a jobs-to-be-done perspective, why are people drilling into these pages anyway? One reason is they're tying to determine if a merge request should be merged despite the pipeline failing due to flaky tests. So navigating from MR to Pipeline to Build requires someone to go back through their browser history (or find a link to the MR somewhere on the build page).
We should render builds in the context of the pipeline. A good solution would not take up an inordinate amount of vertical space and would add value by providing better navigation between builds, and an improved understanding of the build and pipeline.
Proposal
