Longer spool axis

The original axis are too short for my print, they are sometimes stuck and block entirely, so that the extruder moves the whole holder across the table.

So I just lengthened the axis - second attempt so far.

~~Still unsure, if I want to change to make the axis a bit thicker and remix the wheels to add bearings though.~~

And see here for a version of the wheels with space for bearings:

https://www.thingiverse.com/thing:4543758