Improve UI for Mass Rebuild Reports

[kwk]

The last mass-rebuild (#1018) looks like this:

First of all, it is great to see this work in action!!! Kudos!

I wonder the UI can be improved here by saying which Snapshot version was being used in the Mass Rebuild.

Also, does it make sense to pre-analyze the logs of failed builds? We have some logic for this in the snapshot-manager that we probable can rewrite to be used here as well.