Post build report information

## Describe the task

Unity build report has a lot of data we might want but it hides it away in a custom file and only keeps last build around. We want all of it and in a format we might actually do something with even if it's not directly in Unity that we do that.

## Completed When

- [ ] Auto backup each build report to a log folder or similar
- [ ] Show breakdown of size and times

## Additional context

https://docs.unity3d.com/Packages/com.unity.build-report-inspector@0.3/manual/index.html this exists but doesn't allow us to make direct actions or comparisons easily.

It is extremely slow, the ideal would be to generate tables of data to look at in specialised tools.