Improved Leather Edge Paint Roller for m3

I made some improvements on LalinOwl's edge paint roller:

• Added a slide-in flap to adjust the flow of paint.
• Added a small pour lips for easy drainage of leftover paint after use.
• Two different roller designs: coarse and fine flow channels.

Print, cleanup, screw in some 3 mm bolts, and roll!

Video showcase: https://vimeo.com/924539405?share=copy