12V PSU safety cover + 120mm fan modification

Remix of [12V PSU case cover with 120mm fan](https://www.thingiverse.com/thing:2203093) by jolbars.
Added:
* terminals to PSU for wire safety
* 120mm fan dust cover
* mount for PSU onto 2020 extrusion.

Your bed has to be at least 245 x 120mm to print (Supports Tevo Turantula Large bed)

**PSU Setup**
* 1 x PSU Cover
* 2 x M3*12mm Screw (To screw to PSU)
* 1 x [Rocker Switch (KCD3)](https://is.alicdn.com/img/pb/270/936/666/666936270_416.jpg) (rated for mains)
* 1 x [C14 Male Connector](https://www.amazon.co.uk/sourcingmap-Terminals-Panel-Socket-Connector/dp/B00HUHAB0U) (and female connected to mains)
* 2 x M3*12mm Screw (for C14 connector)
* 2 x M3 nut(for C14 connector)
* 2 x [Binding Post Banana Plugs](https://www.aliexpress.com/store/product/Top-Selling-High-Qualtiy-Couple-Terminals-Red-Black-Connector-Amplifier-Terminal-Binding-Post-Banana-Speaker-Plug/402126_32721475121.html)
* 1 x 120mm fan
* 1 x fan dust cover
* 8 x fan self-tapping screw

Solder and hot gl