MKS Gen Z2 v1.1 case

Modified fan grill with honeycomb pattern used on a Sunhokey i3 Prusa Clone S-508 (2015/2017?), inspired by [reisher's design](https://www.thingiverse.com/thing:2756738/) and more information on [Elzariant's design](https://www.thingiverse.com/thing:1666417) about screws, fan placement, etc.

(Not tested yet, but for a MKS Gen 2Z V1.1 board... probably other MKS Gen too.)