Chromebook stand (for 2)

This is a remix of the simple and useful 4-up stand by Magnus. I only needed to support two Chromebooks, and also made a few tweaks:

+ Added a slight angle to the front supports (thinking about my kids being a little careless when sliding the chromebook into place (this will be inside a cubby, so inserted from the front)
+ Thinned out the rear supports a little, just to save material
+ Added a couple of guides in the space between the main holders, to try to avoid an off-angle insertion. Again, thinking here about how gifted my kids are at damaging things :)
+ Added some countersunk screw holes in case it needs to be attached that way (double-stick tape could also work)
+ Added channels to the bottom to allow charging cable to be run from back to front - for a potentially tidier solution. ** NOTE - Cura slicer for some reason filled in some of these channels, and I didn't notice until after my 19 hour print was done. I don't know why it's doing that - will figure out somed