UC2 - Cage system Compatibility insert

This is the [UC2](https://github.com/bionanoimaging/UC2-GIT) insert that adapts our cube to the cage system, commonly used in optomechanics. The pitch of the rods is 30 mm.

It is made for rods with 6 mm diameter. However, every 3D printer is a bit different and when you print the insert the holes might be too loose or too tight for the rods. In that case, open the insert in the Customizer and adjust their diameter by changing the offset (in millimetres).

The offset is a value _added to the diameter_ in the range of (-1 mm, 1 mm).

Find more about the insert in its [GitHub page](https://github.com/bionanoimaging/UC2-GIT/tree/master/CAD/ASSEMBLY_CUBE_Thorlabs_v2).