Our build pipeline takes way too long. Let's move some bits to a daily build instead.

[dumbledad]

Some elements of our PR build pipeline take a long time to run and very rarely fail. This slows down the PR process substantially. We should prune those out and make a daily build which would run on main, and if it took an age that would not matter. Any errors picked up by the daily build would then become high priority issues for us to fix.

AB#4257