customizable Servo Dummies

In order to be able to plan a non-trivial multi-servo model, I made these two servo "dummies". They have roughly the size of a typical 9g micro servo - one of them can be used to illustrate the standard use case in R/C models (with a servo disk or horn), the other one for robotic models (with a servo arm and two joints for better stability)

Servo disk and arm are movable. The **joints may be printed "in-place"** (if your printer is well calibrated) **but require "supports" for their axes**.

Both dummies have been designed using [OpenJSCAD](https://openjscad.xyz/) - the scripts used may be downloaded from here as well. As mentioned before, script constants have been chosen to match the size of 9g micro servos. If you need dummies for different servos, simply adjust these constants, run the scripts within OpenJSCAD again and export the results as (binary) STL files.