Finalize cryo window

[jdkio]

Adds back the cryo window. Also combines fixes from #72 and #73 into a single PR to create the final cryo window design.

From #73,

Removed polyurethane foam material as it is no longer used in cryostat, also removed the auxparam that makes the window sensitive.

From #72,

Adds air to the cryo window. Doesn't try to remove the warm steel after the cryo window, but that can be easily achieved by increasing the dz of the air pocket.

dz = {CompositeWindow:dz}+Q('50mm')

I tried to do that and add a plywood membrane CompositeWindowMembrane, but I was unable to get it to work. This achieves the same thing, though it relies on the accidental coincidence that plywood and our low-density steel have similar densities.

Note that I removed overlaps by moving the cryo window slightly by about z=-0.5x4.765mm. I assume that's within the margins.

Here are the final images. They're almost identical to #72, but the cryo window is moved upstream a small amount. You need to flipbook for it to be obvious

Y vs Z Slice

X vs Z Slice

X vs Y Slice

[github-actions]

Geometry is ready for visual inspection at https://dune.github.io/dunendggd/

[Cjjr2021]

My only concern was the CompositeWindowMembrane volume added, but Jeffrey said that it is not doing anything in the code yet. So it all looks good from my end.

[jdkio]

@ast0815 please merge it if you're happy and pass it on to Alex

[jdkio]

@ast0815, are we good to merge? It's rerunning the checks due to the change log change