PM220 label maker secure mount

Thank you to original author for basis for my update - I don't have Skadis so I removed that part and extended the back up and added mounting holes. I also smoothed out some edges/corners to be a little less sharp. There is a nub that sticks out at the top to hold the label maker in place so when you plug in the power cable or tear labels it doesn't move around. You do not need supports for this. I printed this on both an Ender 3 v3 and the A1 mini to test and both printed without supports and the nub works fine.