Remixed spoolholder

A remix of the spool holder in my futile attempt to make Prusa MK2.5 MMU2 reliable.
Changes:
Stand:
- Narrowed to 109 mm (to fit 5 of these on top of IKEA Lack)
- Gap between the main support structures widened slightly
- Added new tubeholder mount point (giving variation of the filament angle entry to PTFE based on how full the spool is)
- Clipped top off of the horisontal supports

Tubeholder:
- Modified to have a movement stopper
- Modified to fit properly to new mount point

Axle:
- Shortened to 109 mm due to new tubeholder mount point

Hub:
- Shortened to 79 mm to fit into the narrowed stand
- Added strengthening part to the root of the threads after I snapped something like 4 of the ones of the original design