Ender 3 V2 Raspberry Pi 4 Mount Case

# Intro
This model is based on
https://www.thingiverse.com/thing:4751688

I found there is no mount case for RPi 4 and Ender 3 V2. Thus I tinkered one from the existing Ender 3 V2 RPi 3 case.

This case is a single rail mount that could hide behind the Ender 3 V2's control panel.
It is compatible with dual Z-axis motor upgrade and supporting rods upgrade.

#Cooling Design
Case top could mount a 30\*30\*10mm fan for cooling the RPi.
Please use M3 screws to mount the fan. In addition, 15mm long screws are suggested.

The bottom has been cut for better airflow. Thus it is highly recommended to let the fan blow inside the case from the top and let air flee through the bottom.

My RPi 4 could stay below 40°C when running OctoPi for the printer.

#Interfaces Design
All interfaces are accessible except the DSI display port.

#Before Usage
You may suffer from the elephant foot (even very slight could cause some problem). Please read and check this section before deploying