Add more complex install drive selection

[stgraber]

When building an image to install a variety of systems each with a mix of local and potentially SAN storage volumes, it can get hard to get just a single disk selector which works reliably across all machines.

I think we should try to make this easier by allowing for a syntax like:

bus: nvme
min_size: 50GiB
max_size: 2TiB
select: smallest

That would obviously be incompatible with the id property being set.