Sovol SV08 Macro additions + simple upgrade STLs

I have started to develop a little macro collection with little quality of life improvements for the Sovol SV08 Mini 12864 screen. Version 1: **Advanced > Shutdown:** turn off extruder/bed heating, turn on the part fan to cool nozzle below 70°C if necessary, then turn off LED light and carry out a proper shutdown. Flip the power switch when the message "Turn off now" appears on the mini screen **Prepare>Bed:** for some reason there was no separate option to control the bed temperature