ATOMSTACK X7 Pro drag chain holders

### Drag chain holders for Atomstack X7 Pro laser engraver

The purpose of these chains is to prevent cables from interfering while the laser is working. (The cable is going through the chains.) It can also hold air assist hose.
There are 3 parts (one for X axis and Y axis and one that connects both).

It may work on another Atomstack models.

I used this chain: https://www.thingiverse.com/thing:2920060

Full documentation can be found here: https://github.com/pslib-cz/2022-p2a-mme-pppp-CernyDavid