Monocular 8x21 Table support

## Description
The thing is to support a cheap 8x21 monocular on a table for optics experiment. It needs two zipties to fix the monocular. It have an offset triangular groove along with optical axis to align with other equipment.

The attached .fcstd file is the FreeCAD source.

## Improvements
Make model parametric: diameter, number of zipties, height, groove dimensions,...