Avoid double-publishing of Windows images on release day

.NET releases are aligned with Microsoft's Patch Tuesday (2nd Tuesday of each month). Currently the workflow involves double-publishing of .NET's Windows-based images, meaning that new versions of those images are published twice in the same day. It occurs once for updating the .NET version and another for when the new base Windows images are available. We should collapse this down to a single publishing event for the day.

The intent with the first publish is to get the new .NET version available ASAP. In the past, Windows images took a while before they were available. But now they are consistently available at disclosure time. This allows us to delay that first publish and combine everything into one. We can shorten the time it takes to have things published by pre-building them ahead of time, since the Windows images are available internally ahead of disclosure.