Differential Slices for Servicing Updates

This would probably be very tricky to implement, but we could improve upon the differential when building servicing releases by only copying the files that had changed.

This would require us to:
- fetch the "base" release (e.g. 7.4.0)
- Get the latest service release (e.g. 7.4.2)
- Find only the files that have changed since the last release. The .NET BCL DLLs should all stay the same so it should mostly just be SMA and a handful of others
- Copy those files into a new layer

Now when you update from 7.4.2 to 7.4.1, you're downloading a layer that basically only has the changed SMA files rather than what is basically a full zip of the PowerShell installation.

There's little point in doing this between .NET versions since 90% of it will have changed, but it might be a good approach for servicing releases.

This is probably more minmaxxing then is worth the effort, but I might try it just to take on a challenge.

Comienza localizando cómo se crean actualmente las versiones de mantenimiento y las capas de contenedor, y determina después cómo se obtienen y comparan la versión base y la versión de mantenimiento más reciente. Verifica el enfoque con un par de versiones de mantenimiento como 7.4.0 y 7.4.2. Se considera completado cuando una nueva capa contiene únicamente los archivos modificados desde la versión base, mientras que los archivos sin cambios no se copian.

Escrito por el modelo de indexación a partir del texto del issue.