Customizable Telescope Stick

I needed an extendable/portable stick. I couldn't find one that matches my needs so here it is:
A highly customizable telescope stick.

The following aspects can be configured:
- number of segments
- radius, length, wall thickness
- inner/outer thread for extensions (see included ball tip example)
- locking size and strength
- latching size and strength
- latching in retracted position
- printing tolerance

Debug outputs for the resulting maximum extend and radius are given. Various assertions are included to avoid broken configurations. These may only work with OpenSCAD.

Feel free to add more extensions as remix.

Tested with OpenSCAD 2021.01.

Credits to Simon Löffler for the `helix_extrude()` OpenSCAD function.