Planetary system modell

I found [peridot_faceted's script](https://www.thingiverse.com/thing:2360460), but for me not worked, so I rewrited it in openscad.
I let the scale the same as the original version (you can see in the picture where the two trappist-1 are beside each other)
* Add a label text for each star.
* Possible to create the planets hollow.

The main script is the "system.scad".

Available systems:
* Solar system
* Trappits-1: red dwarf with 7 planet
* Proxima Centauri: nearest star with 1 know planet
* Keppler-11
* Keppler-62
* Keppler-90
* Kappa Andromedae: subgiant star, with a super Jupiter planet