Ring with text inside

Proof of concept of an earring with text inside. Uses text on circle from the [text_on OpenSCAD library](https://github.com/brodykenrick/text_on_OpenSCAD).

**Features**

- Configurable gap in the ring
- Text centered opposite of gap
- Customizable - for reasons unknown the thingiverse customizer always closes the gap - use the customizer in OpenSCAD for better results.

**Version history**
v2: Cleanups, merged ring ends with body, removed v1
v3: Cleanups, merged text with body, additional customization options (extrusion depth, vertical text offset), removed v2