racksys - macmini rack mount

a tray for the macmini that works with other @mk_iiim racksys modules to create a rack mountable 1u module for use in a 19in network rack.

possible 1u configurations include:
- left ear, right ear, 2 x macmini trays
- left ear, right ear, mac mini tray, 3 x pi modules

the shallow ears are fine for mix and match with pi modules. use the deep ears when configuring with 2 x macminis side by side.

note that this is not fully compatible with @russross pi system. for other compatible items, look for @mk_iiim library items that are prefaced with "racksys - "

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racksys compatible.

racksys is a modular network rack mounting system for various networking hardware devices.

the racksys system snowballed out of @russross raspberry pi 4 modular rack mount system. starting with developing a tray to hold ethernet keystones to replace an empty pi 4 module, it soon turned into development of a solution to address a need for a rack mountable macmini tray - this was also bui