Prusa mk3 filament guide with bearing & hole

This is a slight remix of an already excellent filament guide (see edsped's description). My only change was to add a hole to allow holding filament that is not in use (which makes it easier to have multiple spools below the table).

I've made an [editable version](https://cad.onshape.com/documents/3081f27c33a5e344f172f2ec/w/dfb1b71aae3c5bfcc9ba6e02/e/6c0a4fdee10ce9219d06953c) of this file in onshape, in case you'd like to tweak further.