test: Add basic UI for viewing and restarting builds

I was finding myself continually scrolling through the runner log file to see if builds had failed and to grab their log urls, so I've added a very basic UI for viewing builds, with the added function of being able to restart builds.
This should be sorted by timestamp. Maybe put it in the key name (as an index) so that we don't have to go through all of the builds to render this.