Spike: Hold-and-drag interaction for the pipeline graph horizontal scroll

Problem

The horizontal scrollbar is hidden from the user at the bottom of the page, on long pipelines. This makes it very frustrating to scroll from left to right. One has to first 'scroll all the way down, then back up again. And if the desired view is not realized, this has to be repeated. While true, on a touchpad or a mouse with horizontal scroll, this can be avoided, but horizontal scrollwheels are not the norm.

Proposal

Investigate if we could implement a hold-and-drag interaction on the pipeline graph to allow users to navigate the graph horizontally without having to scroll all the way down first.

This is a spike issue for #243784 (closed)