Github action workflow 'timeline' view.

**Is your feature request related to a problem? Please describe.**
Right now it is difficult to visualise how long a workflow ran for, especially if there is a workflow with lots of parallel / dependent steps. I know you can look at the durations etc, but a nicer visualisation is missing.

**Describe the solution you'd like**
When clicking on / viewing a completed workflow run, have some kind of horizontal 'timeline' view. You'd have horizontal bars indicating how long each job / step ran for.

**Additional context**
Add any other context or screenshots about the feature request here.