DIN Rail Stand v3

This is a [DIN Rail Stand v2](https://www.thingiverse.com/thing:2144527) remix that adds a modeled M4 thread. I also uploaded STL for a version of this stand with a slot for [AC IEC socket](https://botland.store/wires-and-power-connectors/9457-ac-iec-male-connector-with-latch-with-switch-5904422313395.html).