Prusa Spool Holder Adapter

I'm a fan of the [TUSH Ultimate Spool Holder designed by filamentry](https://www.thingiverse.com/thing:2047554), as well as the associated [TUSH #PARALLEL UPGRADE# for "Ultimate Spool Holter V2" & "V2+" by Devilscave](https://www.thingiverse.com/thing:4460406), which allows you to keep the spool holder in parallel.

However, I recently picked up an [Original Prusa Mini+](https://github.com/prusa3d/Original-Prusa-MINI) which came with a rail adjustable spool holder, which is similar enough to the TUSH spool holder, but the dimensions are a bit larger.

Rather than tossing the Prusa spool holder and printing a new TUSH spool holder, I opted to remix the parallel adapter, making it a little bit wider and a little bit longer so that the Prusa spool holder would fit.