Spool flexible infill and indicator

I made the following improvements compared to the default Bambu spool and other 3D-printed spools available online:The leftover-filament indicator is printed directly into the model with precise positions, unlike the default BambuLab label, which is in equal distance (and that's wrong!)The filament-type indicator is also integrated into the print. You can insert a small piece of filament to mark the material (compatible with most Bambu refill materials: PLA, PETG, HF, CF, matte).More space for filament anchor holes to make life easier;The surface pattern is generated from the slicer infill, allowing users to customize it with any pattern and density they like. And it saves a lot of time.The radial ribs are intentionally exposed