Multi-zip tie mount

Inspired by this one, but for multiple cables, and with a screw hole in the middle.
https://www.thingiverse.com/thing:1800896
Also get a look to this one : https://www.thingiverse.com/thing:447995

v02 : Prints well with no support, added the small notch for easy removal from the print bed.

v03 : Added the rails after each output to have the zip tie point upward and ease zip installation.