PiNAS Heated Inserts

I couldn't get the original file, or easily import and use the STL, so I had to pain staking re-model it as close as I could to the original.

With the exception of adding heated inserts instead of captive nuts.

**careful** Designed for short heat inserts: 4.5mm * 4mm. But the CAD is included if you need to make it work for your particular heat inserts