Add M4 Mac Mini 1.5U Mount with 1x LabStack Module

> @GarnetSunset single or dual M4 Mac Mini 10inch rack would be amazing, probably 3D printed to save on cost!
> myelectronics.nl has already showcase it's possible for 19" rack > [Link](https://www.myelectronics.nl/us/19-inch-125u-rack-mount-for-3x-mac-mini-2024.html)
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> For a 3D printed mount, it would end up being closer to 1.5U rather than the 1.25U of that mount, just to make sure there's enough material for the weight of the Mac Mini, and for a 10" rack, you wouldn't be able to get more than one Mac Mini.
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> The total opening width on the 10" rack is ~222mm (8.75"), and each M4 Mac Mini is 127mm (https://www.apple.com/mac-mini/specs/).
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> Thinking out loud, I could probably make a 1.5U mount for the M4 Mac Mini, plus a single LabStack module on its side, and MAYBE a keystone jack for the MacMini's Ethernet port and/or HDMI port. I could DEFINITELY make a 2U version, but would still only be able to add a single LabStack module, but it would allow multiple keystone jacks for the Mac Mini...
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> Let me know if there's interest, and I'll see about adding it to my list for LabStack modules (so long as Jeff doesn't mind the hijack).

_Originally posted by @JaredC01 in [#56](https://github.com/geerlingguy/mini-rack/issues/56#issuecomment-2600975826)_

Start by reviewing the existing LabStack mount designs and the linked 19-inch Mac Mini reference, then compare them with the 10-inch rack dimensions in this issue. Done means a defined 1.5U 3D-printed mount that accommodates one M4 Mac Mini and one LabStack module, with any keystone-jack options resolved.

Written by the indexing model from the issue text.