4pin PC fan pass through grommet

Allows to mount 4pin PC fan cable extender as externally available fan port.

There are  versions of gromet

• nokey - can rotate in mounting hole
• key - has small notch that blocks rotation in hole
• noround - has mounting hole shape that prevents rotation

Required mounting hole is 20mm.

Threads created using library: https://www.thingiverse.com/thing:1686322