Ender 3 Bed Leveling GCode + Test Print

2021-03-20:
Added 32-bit board bed leveling GCode.

2020-10-05:
This is a remix of CHEP's bed leveling GCode and test print for the Ender 3/Ender 3 Pro running the 8-bit board.

Modifications to GCode:
- Increased movement speed during X-Y motion
- Added parking sequence which moves the nozzle away from the bed after leveling. (prevents starting a print and preheating nozzle too close to the BuildTak magnetic bed)

Modifications to test print:
- Reduced test print height (from 10 to 2 layers when using 0.2mm preset)