Parametric universal spool holder with variable number of cutouts

This is a rework of the Parametric universal spool holder by rowokii

Changes made:
- used generator expression for creating material saving cutouts,
This allows to use a different number of cutout. Looks good with 5 cutouts.
- added a tiny cylinder as support for easier printing of the hole of the bearing.
This support can (and should) be broken away after printing.
- increased default diameter of bearing (+0.6mm) and rod (+0.3mm) for easier fit.

**UPDATE**
After printing this